Description
Enterprise Resource Planning (ERP) is the technology that provides the unified business function to the organization by integrating the core processes. ERP now is experiencing the transformation that will make it highly integrated, more intelligent, more collaborative, web-enabled, and even wireless.
152
ABSTRACT Enterprise Resource Planning (ERP) is the technology that
provides the uni?ed business function to the organization by integrating the
core processes. ERP now is experiencing the transformation that will make
it highly integrated, more intelligent, more collaborative, web-enabled, and
even wireless. The ERP system is becoming the system with high vulnerabil-
ity and high con?dentiality in which the security is critical for it to operate.
Many ERP vendors have already integrated their security solution, which may
work well internally; while in an open environment, we need new technical
approaches to secure an ERP system. This paper introduces ERP technology
from its evolution through architecture to its products. The security solution
in ERP as well as directions for secure ERP systems is presented.
KEYWORDS authorization, Enterprise Resource Planning,
exchange infrastructure, policies, RBAC, Web services
INTRODUCTION
Enterprise Resource Planning, a business integration approach, has been
widely deployed in various kinds of organizations since it was ?rst de?ned
by the Gartner Group in 1990 as the next generation of Manufacturing Busi-
ness System and Manufacturing Resource Planning software. Today, ERP is
considered to be “the price of entry for running a business” (Kumar and van
Hillegersberg, 2000).
An ERP system is an integrated, con?gurable, and tailorable information
system which plans and manages all the resources and their use in the enter-
prise, and streamlines and incorporates the business processes within and
across the functional or technical boundaries in the organization. With ERP,
an enterprise can automate its fundamental business applications, reduce
the complexity and the cost of the collaboration, force the enterprise itself
to take part in the Business Process Reengineering (BPR) to optimize its
operations, and ?nally result in a successful business.
The objective of this paper is to give an overview of the state of the art
in ERP technology and the security issues for an ERP system. In particular,
Address correspondence to the authors
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Address correspondence to the authors
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Security for Enterprise
Resource Planning Systems
Wei She and
Bhavani Thuraisingham
University of Texas at Dallas,
Richardson, TX, USA
Information Systems Security, 16:152–163, 2007
Copyright © Taylor & Francis Group, LLC
ISSN: 1065-898X print/1934-869X online
DOI: 10.1080/10658980701401959
153 Security for Enterprise Resource Planning Systems
we discuss the evolution of ERP, its key compo-
nents, the status of vendor products, and what has
been done with respect to security. Our research as
well as plans for secure ERP systems will also be
discussed.
The organization of this paper is as follows. The
history and evolution of ERP systems will be given
in the next section. ERP technologies and frame-
work including the communication platform such
as EDI, ALE, and Exchange Infrastructure are pre-
sented in the “ERP Technology” section. This section
also includes a discussion of the ERP architecture,
some aspects of SAP, and the emerging web ser-
vices for ERP. Major ERP vendors and their products
are discussed in the “Vendors and Products” section.
Security issues for ERP systems are discussed in the
following section, “Security in ERP.” In particular,
the overview of the ERP security using a layered
approach, as well as the RBAC model for ERP is dis-
cussed. We will compare these security features with
the authorization function in SAP R/3 system and
the Baan security solution. Some of our researches
in ERP as well as trends are discussed.
HISTORY OF ERP SYSTEMS
AND APPLICATIONS
The history of ERP traces back to the 1960s, when
most organizations were developing the centralized
computing systems using Inventory Control Pack-
ages (IC) in order to automatically manage a com-
pany’s inventories. These legacy systems are mostly
based on programming languages such as COBOL
and FORTRAN. In the 1970s, Material Requirements
Planning (MRP) systems were developed to man-
age the requirements and plan production. Later,
Manufacturing Resources Planning (MRP II) system
emerged in the 1980s, aiming to optimize the manu-
facturing process. The concept of ERP was intro-
duced in the early 1990s as an enterprise-wide and
across-functional integration of the core organiza-
tional business processes, including manufacturing,
distribution, accounting, ?nancial, human resource
management, project management, inventory man-
agement, service and maintenance, and so on. From
the point of views of some researchers, the ERP
technology after 2000 is considered as “Extended
ERP” (Rashid, Hossain, and Patrick, 2002) because
e-business solutions such as Customer Relationship
Management (CRM) and Supply Chain Management
(SCM) are included into the core modules of original
ERP systems.
ERP has a wide range of applications in both
industrial and non-industrial areas such as aerospace
and defense, banking, consumer products, construc-
tion, healthcare, education and research, insurance,
raw and processed materials, logistics, transporta-
tion, wholesale, public sectors, telecommunication,
and so on. In the early years after ERP emerged,
deploying and maintaining an ERP system was
expensive and took a relatively long time to recover
costs. Since then, the implementation and mainte-
nance cost of ERP system was greatly reduced due
to the retro?t of technical infrastructure. Nowadays,
many light-weight ERP applications are developed
for small and medium companies.
Various commercial products, including SAP, Ora-
cle, and Baan, are now available in the marketplace.
Furthermore, Web services and service-oriented
architectures are the major underlying technologies
for emerging ERP systems.
ERP TECHNOLOGY
Overview
ERP systems have evolved extensively over the
years. Initially, such systems were used for simple
functions such as accounting and human resources
planning. With the advent of Web technologies,
companies such as Oracle, SAP, and Baan began
developing a suite of applications for ERP systems.
The emerging technologies such as Web service
and eXtensible Markup Language (XML) have had a
major impact on ERP systems.
In this section, we discuss the various compo-
nents of ERP systems. We start with a discussion
of its architecture and various business components
in the next section including ?nancial management,
human resource management, production lifecycle
management, customer relationship management,
and manufacturing management. In the “EDI, XML,
and Information Exchange” section, we discuss
exchange infrastructure, the cornerstone of ERP sys-
tems. In this section, we also discuss the two tech-
nologies for exchanging electronic documents among
She and Thuraisingham 154
different entities: EDI and XML. Finally, emerging
Web services and their relationship to ERP systems
are discussed in the ?nal section, “Web Services.”
ERP Architecture
There are many disadvantages to MRP II and MRP
technologies. In an enterprise, some systems may
be developed by the enterprise itself, while others
may be developed by different vendors using differ-
ent databases, languages, and technologies. Systems
differ from each other, which makes it dif?cult to
upgrade the organization’s businesses, strategy, and
information technologies effectively. With the com-
munication infrastructure and ERP functionalities
encapsulated in components, an ERP system can
easily meet these requirements. A typical ERP sys-
tem should at least have the following features:
Componentized—different business functional-
ities are designed as different components.
Integrated—components are integrated and seam-
less data ?ow between components allows them
to collaborate as a one function.
Flexible—system is expandable and compatible
with the old systems, the change to the business
processes and strategies are easy to ful?ll (Glass,
1998).
Tailorable—system should be easily con?gured
according to the enterprise’s needs.
Real-time—the components work in real time,
online, and batch processing modes should be
available.
Pro?table—system must have the potential to
reduce the cost or increase pro?t, since these are
a company’s basic requirements and motivations.
Secured—security schema has to be enforced to
protect various enterprise resources regardless
whether it is appropriate or suf?cient.
The business logic in ERP system employs client/
server architecture to create a distributed computing
environment. Generally, the three-tier architecture
will be used, which contains three layers of logic:
1. Presentation Layer (Front): A uni?ed Graphi-
cal User Interface (GUI) or browser that collects
input, generates requests, and returns the results
back to the user.
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2. Application Layer (Middle): Application programs
that collect the requests from the Presentation
layer and process the requests based on the busi-
ness rules, functions, or logics.
3. Database Layer (Back): DBMS that manages the
operational and business data throughout the
whole enterprise and the user access to this infor-
mation. This layer may also include the operating
system and the related hardware (Sprott, 2000),
since they are necessary for the system but trans-
parent to users.
As the basis of the ERP system, an information
exchange platform such as SAP NetWeaver will
always be deployed before implementing ERP soft-
ware. After consolidating the business logic and the
technical platform, we will have the ERP system
architecture as showed in Figure 1.
The components that different ERP vendors
provide may vary, as they will always have some
inclines due to the historical problems, yet the core
functionalities are nearly the same. These function-
alities include (Bakry and Bakry, 2005; Shehab et
al., 2004):
Financial Management, which may includes the
functionalities such as collection and payment
management, payables and receivables manage-
ment, assets and properties management, cash
management, loans, ?nancial consolidation, gen-
eral ledger, treasury management, and planning
and budgeting.
Human Resource Management, which may have
the functionalities such as payroll management,
self-service, learning management, bene?ts,
recruitment, tutor, timer and labor management,
and compensation management.
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Da t a ba s e
L a y e r
R
D
B
M
S
Graphi cal User I nterface
Exchange I nfrastructure
F I N B I P L M C R M S C M S R M H R Lega c y
Pr es ent at i on
L a y e r
Appl i c at i on
L a y e r
Communi cat i on
Pl a t f or m
FIGURE 1 The Architecture of Enterprise Resource Planning
155 Security for Enterprise Resource Planning Systems
Manufacturing Management, which will provide
the functions such as discrete manufacturing, pro-
cess manufacturing, ?ow manufacturing, manufac-
turing scheduling, and shop ?oor management.
Sales, Distribution, and Logistics Management,
which includes the functions as order capture, ser-
vices, sales, sales incentive management, pricing,
logistics, bulk stock management, inventory man-
agement, warehouse management, requirements
management, and strategic account planning.
Customer Relationship Management (CRM), which
maintains the relationships between the organi-
zation and its customers and includes function-
alities such as collecting, storing, and analyzing
customer information.
Product Lifecycle Management, which manages
the entire lifecycle of a product from conception
and design to manufacture, service, and disposal.
Supplier Relationship Management (SRM), similar
to CRM which deals with customers, SRM man-
ages the supplier relationships by collecting, stor-
ing, and analyzing supplier information.
Business Intelligence, whose concept has a wide
range covering all the processes performing anal-
ysis and/or evaluation which either work at the
strategy level, tactical level, or operational level
by providing instruction for optimizing business
performance. Demand management can be clas-
si?ed into this category.
Supply Chain Management (SCM), which is another
concept having some overlap with above compo-
nents. An SCM can include the business processes
such as CRM, SRM, manufacturing management,
demand management, and production planning.
The key point is that these business processes
have to be connected across organizations in order
for a business success of supply chain. These pro-
cesses are inter-organizational, thus may be either
included in or excluded from the scope of ERP.
With the de?nition of extended ERP, we no longer
consider ERP as internal within an organization.
The scope of the term “ERP” is a bit confusing
when comparing it to the term “e-commerce.” Gen-
erally speaking, ERP is more concerned with the
internal functionalities in an organization; on the
other hand, e-commerce or e-business focuses on
the business across companies. While under current
global business strategy, companies are no longer
?
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?
?
?
?
?
competing with each other as individuals, coordi-
nation enables several companies to compete as a
whole. SCM literature discusses much in this area,
and people are considering a supply chain as the
competition unit. With coordination, we cannot
always assume that some components are working
internally and some others are working externally.
Thus, the boundary between ERP and e-commerce
is blurred in many cases; and it is inappropriate and
unnecessary to discuss the technical issues from the
narrow concept of ERP (internal).
EDI, XML, and
Information Exchange
Electronic Data Interchange (EDI), also called
“paperless exchange” (Nagpal, de Bruyn and Lyfareff,
1999), is the technology that allows enterprises to
exchange business information between separate
computer systems, using a standard structured for-
mat (ANSI ASC X.12 in the late 1970s and EDIFACT
in the 1980s) over a communication network. EDI
technologies such as SAP’s exchange infrastructure
(White Paper, SAP Exchange Infrastructure 2.0, 2002;
White Paper, SAP R/3 Enterprise, 2002; White Paper,
SAP Exchange Infrastructure 2.0 Technical Infrastruc-
ture, 2002) have been in place for many years as the
footstone of all ERP technologies. Although those
systems implementing EDI exchanging documents
have become legacy systems today, the major contri-
bution from EDI technology, the business semantics,
is preserved by combining EDI and XML.
XML (W3C, 2006) is a ?exible text format standard
developed by the World Wide Web Consortium (W3C).
It is a simpli?cation of Standard Generalized Markup
Language (SGML) for originally large-scale electronic
publishing and later as the standard for exchanging
various data over the Web. The major advantage of
XML over other description languages (e.g., HTML)
is its ability to represent the data format using Docu-
ment Type Declaration (DTD) schema or XML schema
(W3C, XML Schema Part 0, 2004; W3C, XML Schema
Part 1, 2004; W3C, XML Schema Part 2, 2004). This is
the reason XML is applied in many ERP applications
developed in recent years. XML-based document
exchange removes the obstacle faced by most small
and medium organizations—high implementation
and maintenance costs of exchanging infrastructure
She and Thuraisingham 156
(Iacovou, Benbasat, and Dexter, 1995). Frameworks
such as xCBL (Common Business Library) and lan-
guages such as ebXML (OASIS, 2001; OASIS, 2006)
were designed in recent years to support enterprise-
wide applications by combining the business seman-
tics of EDI technology and the ?exible and innovative
data model of XML. Furthermore, a new trend among
organization management is towards knowledge-
based management, which means that resources lying
within an ERP system are now viewed as knowledge
instead of information or data. This trend starts by
distinguishing among three concepts: data, informa-
tion, and knowledge. Data are simply raw numbers or
facts, information is processed data, and knowledge is
information processed in the mind of a person. Thus,
knowledge may have more various representations
that must be supported by the description languages.
This is another reason exchanging infrastructure now
becomes XML-based.
Web Services
Thuraisingham (2006) stated that we are now in
the third wave of ERP systems. The ?rst wave related
to manufacturing applications; the second was spe-
cialized applications such as supply chain manage-
ment; and the third was based on Web services.
The use of Web services eases integration and
also reduces costs. Clients want to access informa-
tion without having to go through ERP software.
Therefore, with the use of Web services and the
composition of Web services, clients as well as
outsourcing vendors can access many of the ERP
applications seamlessly. These applications include
checking bank accounts, placing orders, and other
services. Reduction in cost comes from the fact that
clients can communicate with legacy ERP software
through Web services and do not have to deal with
the complexities of the software. Also ERP vendors
are introducing the Web scenarios broker hub that
will act as a broker between Web services and the
ERP software. SAP offers this hub through mySAP
and Oracle via its e-business suite.
VENDORS AND PRODUCTS
In this section, we provide an overview of the
major ERP systems vendors. SAP is one of the most
prominent vendors of ERP. Other vendors include
PeopleSoft and Baan. However, PeopleSoft has been
purchased by Oracle, and Oracle is emerging as
a major ERP systems vendor. Furthermore, Oracle
provides the server technologies that ERP appli-
cations could utilize, while SAP and Baan rely on
various vendor products for server technologies. We
will provide an overall discussion about the prod-
ucts provided by SAP, Baan and Oracle. Note that
Baan has been purchased by SSA. Microsoft is also
becoming a major player in ERP software.
SAP ( Systems, Applications, and Products
in Data Processing ) was formed in 1972 by ?ve
former IBM employees in Germany. SAP focuses on
the development of application software for real-
time business processing, beginning with its ?rst
accounting software developed in 1973. Its ?rst ERP
product, SAP R/2, was developed in the late 1970s
using a centralized database and dialog control sys-
tem. In the 1990s, SAP R/3, which uses the three-tier
architecture of database, application, and user inter-
face, was unleashed on the market. R/3 was a break-
through, making SAP the largest vendor in the ERP
market by 1999. By 2005, there were around 100,000
installations worldwide, more than 1500 partners,
over 25 industry-speci?c business solutions, and
more than 30,000 customers in over 100 countries.
SAP now owns 26% of CRM market share, 29% of
ERP market share, and 19% of SCM market share
by total software revenue. SAP NetWeaver uni?es
the integration technologies into a single platform,
which lays the groundwork for the integration all
systems SAP runs or non-SAP software. It is the basis
of SAP ERP applications, partner solutions, and cus-
tom-built applications. SAP R/3 is the third genera-
tion set of highly integrated software that performs
the core business functions within a company; while
mySAP, which also includes R/3 component as an
important building block, is intended to empower
the collaboration between organizations. mySAP is a
Web-based e-business suite.
Oracle, which was founded in the 1970s in
the USA, is most famous for its well-known rela-
tional database Oracle and is the second-largest soft-
ware company in the world. In 1987, Oracle offered
its ?rst ERP software—Oracle General Ledger. In the
following years, Oracle developed other ERP soft-
ware such as self-service applications, strategic pro-
curement solution, ?nancial consolidation engine,
157 Security for Enterprise Resource Planning Systems
and ?ow manufacturing product. Oracle’s ERP sys-
tem is now known as Oracle E-business Suite, which
has more than 50 different modules covering the fol-
lowing areas: ?nance, accounting, human resources,
manufacturing, supply chain management, project,
and front of?ce. Oracle also has many other well-
known products in other ?elds such as database,
data warehousing, and work?ow. After the acquisi-
tion of PeopleSoft and JD Edwards in 2004, Oracle
gained approximately 22% of the ERP market share.
PeopleSoft Enterprise is the business application
suite that offers Web services integration with multi-
vendor and homegrown applications; it is admittedly
considered easier to con?gure and more ?exible than
its competitors. JD Edwards EnterpriseOne and JD
Edwards World are both the business applications
from J.D. Edwards Company, which has extensive
experience supplying software for the IBM iSeries
platform. JD Edwards World provides the Web-
enabled applications for the management of plants,
inventories, equipments, ?nances, and people.
Sage, founded in England in 1981, entered
the ERP market and gained a solid market share
using the strategy of acquiring small ERP vendors
such as Tetra and Interact Commerce Inc. By 2005,
Sage had revenue of $1.4 billion in the ERP mar-
ket and claimed 6% market share as the third-largest
ERP vendor. Sage Line 500 v6 is newest version of
the Sage Line 500 product family, which is the Web-
based integrated ERP solution covering core func-
tionalities in a company. Sage 1000 is new, single
business management software designed to offer the
operations within mid-size organizations.
Microsoft, founded in 1975, is the biggest
software company in the world with its famous
Windows series products. Microsoft Business Solu-
tion Group (MBS) is the department that focuses on
providing ERP solutions, such as Microsoft Dynam-
ics (formerly Microsoft Business Solutions), which is
the integrated business management solution that
includes ?nancials, customer relationship manage-
ment, and supply chain management. By 2004, MBS
had revenue of around $800 million, giving it a 4%
ERP market share.
Others. In addition to the major vendors, there
are several other ERP vendors that are emerging. In
2004, the biggest ERP vendors—SAP, Oracle, Sage,
Microsoft, and SSA—accounted for around 70% of
ERP market share by revenue. The other 30% was
shared by other ERP vendors such as Geac, Intentia,
Infor Global Solutions, and Lawson.
SECURITY IN ERP
Overview
Security is critical for ERP systems, as they are
used in numerous industries including defense,
intelligence, medical, and ?nancial. First, we need
to develop a security policy and a model for ERP
systems. Many of the current systems focus on con-
?dentiality aspects of security. In this section, we
discuss the developments as well as current trends
in security for ERP systems.
In the “Approaches to Security” section, we dis-
cuss what needs to be secured. In section “Cur-
rent Solutions,” we discuss current developments,
including security, for SAP. In the “Next-Generation
Models” section, we discuss some of the next-gen-
eration security models. In the concluding section
“Directions on ERP Security,” we provide an over-
view of trends, including a discussion of security
policies and Web services security.
Approaches to Security
Security problems exist in every facet of an ERP
system. These facets can be classi?ed into three cat-
egories: network layer, presentation layer, and appli-
cation layer, which includes business processes,
internal interfaces, and database.
When a customer/partner communicates with an
ERP system, or the business components located in
different places interact with each other, the secu-
rity problems in these cases are classi?ed into the
network security domain. ERP experts will not deal
with these cases directly, instead this function will
be provided by purchasing from other vendors who
are experts at network security.
The presentation layer refers to the graphical user
interface, browsers, and PCs. Since the transmission
of GUI packets is impossible to restrict, ERP experts
cannot secure the system by limiting user access to
GUI. The better way to provide security may be to
place a CITRIX server between the user and the ERP
system.
She and Thuraisingham 158
The security in application layer invests large
efforts of the ERP experts to offer an effective way
to secure the business data and processes. The
technicians will also choose to activate/deactivate
the security functions provided by the database ven-
dor according to the overall security solution. Van de
Riet, Janssen, and Gruijter (1998) summarized some
of the security aspects in an ERP system:
Security policy and administrator: ERP experts
have to provide such a way that explicit and well-
de?ned security policies can be easily de?ned
and maintained. The security policies will offer
the rules for the access of subject to object, and
these are the constraints put on the administra-
tors when they are granting/denying permissions
to the users.
User authentication: to verify whether the user is
the same person as he claims.
Separation of duties: tasks must be classi?ed such
that certain tasks can only be performed by cer-
tain users or roles.
Authorization: to verify whether the user has
access to the relevant resources. Depending
on the authorization rules, the user is granted
access.
Time restriction: the access is permissible only
during certain time.
Log and trace: the logging and tracing of relevant
events has to be done with preventing the log
?les from breach.
Database security.
Essentially we need end-to-end security for ERP
systems. The next three sections discuss some of the
current trends and directions for secure ERP.
Current Solutions
Role-Based Access Control
Many of the current systems are based on Role-
Based Access Control (RBAC), although they may
have different settings of either enhancements (Kern
et al., 2002) or simpli?cations. This model (Figure 2)
de?nes roles and grants certain access rights. Accord-
ing to Sandhu et al. (1996), an RBAC model consists
of the following components:
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Permissions: Permission is the access to one or
more objects in the system. The permission has
different meanings in different environment. If in
a database system, the permission refers to the
rights such as select, update, delete, or insert a
record. If an accounting application, it may be the
rights such as account creation/deletion, credit/
debit, and transfer (Sandhu et al., 1996).
Roles: A role is a named job function within the
organization. A role may be hierarchical. For
example, an engineer role is also an employee
role.
Users: A user is a person who may be assigned
one or more roles.
Constraints: In the system where there is only
one single administrator, the constraints may be
meaningless. If the administration is decentral-
ized, meaning there are several administrators,
the constraints will be used by the senior admin-
istrator to restrict the junior administrator’s right
to grant/deny the permissions.
Authorization in SAP R/3
Some of the concepts involved in the authori-
zation in SAP R/3 system are listed below (White
Paper, Authorization Made Easy, 2000; Goodman,
2004; Schaad, 2006):
Authorization object, which represents the autho-
rization concept and consists of some authoriza-
tion ?elds.
Authorization, which is an instance of one autho-
rization object and de?nes the permitted value
range of each authorization ?eld of the authoriza-
tion object.
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Role User
Permi-
ssion
Session
Constraint
User-to-role
Assignment
Role-to-permission
Assignment
Role-
Hierarchy
FIGURE 2 The Model of Role-based Access Control [6]
159 Security for Enterprise Resource Planning Systems
Authorization pro?le, which contains some autho-
rizations which are assigned to the user by the
administrator.
Authorization check, which is used to protect the
transactions or data you choose and is embed-
ded in the program logic. When the authorization
check is performed, the authorization pro?le will
be used to compare the required values to run the
speci?c transaction.
User master record, which enables the users to
log on to the R/3 system and grant limited access
to the transactions and data.
Pro?le generator is the component which helps the
administrators create, generate, and assign autho-
rization pro?les using activity groups and user.
A pro?le generator may have the following
components:
Activity group is a collection of activities such as
tasks, reports and transactions. An activity group
usually represents a job in the enterprise. An
activity group can have many users assigned to it,
and a user can also be assigned to many activity
groups. An activity group can be assigned to the
following types of users: user ID, job, and position.
Job represents the general classi?cation of duties.
Position represents a person’s detailed individual
assignment within an enterprise. The difference
between job and position is that job is just the title
which does not imply what projects you will do in
the company, while position does so.
Composite activity group is the collection of sev-
eral activity groups.
User assignment is the task that assigns one or
more users/roles/positions to one or more activity
groups or composite activity groups.
Another important concept in the authorization
in R/3 is authorization administration, which means
whether the creation, generation, or assignment of
authorization is centralized or decentralized (one or
more administrators).
Through these concepts, we may learn that
the mechanism of R/3 authorization is actually an
instance of Role-Based Access Control Model, except
that it contains some elements speci?cally used in
R/3 environment. Figure 3 provides a visual under-
standing of the model of authorization in R/3 system.
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Furthermore, Logging and Tracing is also a required
component to secure the application layer of ERP
system, although it is not the key function.
Baan Security using DEM
In Baan (bought by SSA) security architecture
(Valente, 1999), we can easily determine if the solu-
tion is based on the RBAC model. Baan security solu-
tion uses a tool called Dynamic Enterprise Modeler
(DEM) to assist the security con?guration of Baan.
DEM is used to model business processes or func-
tions of an organization and de?ne the roles. Within
the architecture of Baan’s security solution, there are
four concepts: User Employee, Role, and Process.
User: Baan user is the pro?le including all of an
employee’s personal information.
Employee: The person who works in the
organization.
Role: De?ned to indicate the position and the
assignments of the employee. All employees must
be assigned to a role, and roles will be assigned
to the business processes.
Process: Once a process is modeled in Baan ERP,
roles will be attached to that process.
Next-Generation Models
Extended RBAC
Most contemporary ERP software adopts tradi-
tional access control methods such as RBAC as its
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Auth.
Field
Auth.
Field
Auth.
Field
Au t h .
Obj ect
Auth.
Value
Auth.
Value
Auth.
Value
Aut hor i -
zat i on
Pr of i l e
Auth.
Profile
Auth.
Profile
Auth.
Profile
Us er
User
Role
Positio
n
Pr of i l e
Gener at or
Act. Group
FIGURE 3 The Model of Authorization in r/3
She and Thuraisingham 160
primary measure to secure the system. What these
methods care is whether some subject is allowed to
perform the requested rights on the object. In some
cases, the subject has to meet mandatory require-
ments before exercising the rights. A good exam-
ple is that the researchers have to ?ll up his/her
personal information before he can have the rights
to read or download white papers. This mandatory
requirement is Obligation (Park and Sandhu, 2004).
Another important requirement for accessing the
resources is the environmental or system require-
ment called Condition (Park and Sandhu, 2004), such
as accessing time, date, and location. Since these
functional predicates are not included in the idea of
traditional access control methods, a straightforward
enhancement of RBAC today is to introduce obliga-
tion and condition predicates. So we have so-called
Extended-RBAC.
In this ERBAC model, an extra decision manager
is added since obligation and condition predicates
will be taken into account. In the decision process,
condition requirements will be checked ?rst; if all the
environmental conditions are met, the checking pro-
cedure for the obligations will be triggered; and, at
last, the decision process will check whether the user
is intended to access the information. Srinivasan and
Thuraisingham are examining the extended RBAC
model for ERP (Srinivasan and Thuraisingham, 2006).
UCON
In recent years, a new model, Usage Control
Model (UCON), was proposed in order to set up
a framework for the future security techniques in
ERP. UCON not only integrates three functional
predicates (authorization, obligation, and condition)
but also brings in the concept of time. This feature
allows a security component in ERP system to be far
more dynamic (Park and Sandhu, 2004).
The UCON model consists of the following core
components:
Subject and subject attributes: An entity with asso-
ciated attributes which holds or exercises some
certain rights on objects.
Object and object attributes: An entity with asso-
ciated attributes which one or several subjects
hold or exercise rights on.
?
?
Rights: Privileges that a subject can or cannot
access an object.
Authorization: Functional predicate determining
whether a subject is allowed to perform some
right on an object.
Obligation: Functional predicate verifying
whether the mandatory requirements have been
ful?lled before a subject performs some right on
an object.
Condition: Functional predicate that checks whether
the current environmental or system status allows
a subject to perform some right on an object.
The UCON model is a large model family in
which different combinations can exist for the
three predicates. If we regard the UCON mod-
els with only one of these predicates used as the
leaf nodes, we can build a tree rooted at UCO-
N
ABC
model. We denote these models as UCON
A
,
UCON
B
, and UCON
C
. These models can be broken
into several submodels based on whether time is
taken into consideration. For example, UCON
A
will
be divided into UCON
preA
and UCON
onA
. Further-
more, these submodels can be divided into more
detailed models depending on when and whether
the update of mutable attributes will occur. We are
currently investigating the applicability of UCON
features for ERP security.
DIRECTIONS ON ERP SECURITY
Trends
Looking into the history of ERP technology, it is
easy to ?nd that the transformation from mainframe
structure into client/server architecture is its big-
gest step. With this architecture, it became possible
to develop a large system which integrates lots of
functionalities. Now, ERP becomes the core of the
operation and business in a company. ERP will not
always remain the same as the requirement of auto-
mation of business evolves. The future ERP system
may have the following features:
Heterogeneous: Heterogeneous/heterogeneity
means that the components from different ven-
dors coexist and cooperate in an ERP system.
It has two prerequisites: componentization and
?
?
?
?
?
161 Security for Enterprise Resource Planning Systems
integration. It is true that some of the leading
ERP vendors are going to or have already done
something regarding these two aspects. Stronger
communication platforms are provided to support
heterogeneous applications, and applications are
developed in the form of components.
Collaborative (Jayaweera, Johannesson and
Wohed, 2001): This could be in the realm of e-
business. We can classify the business processes
within an enterprise into two types: enterprise-
centric process and collaborative process. Pro-
cesses such as accounting and payroll processing
are enterprise-centric; others such as supply chain
management are almost completely collaborative.
There are some intervenient processes, yet they
are designed and developed in an enterprise-cen-
tric way. In the future, more processes will be
redesigned in a collaborative way. This feature
also implies the ERP system will be more open
and more Internet-based.
Intelligent: ERP system in the future will include
more components that do the analysis, investiga-
tion, or even advice on the strategic transform.
This feature implies that more con?dential infor-
mation will ?ow within or out of an ERP system.
Knowledge-based: Firms are moving towards
knowledge-based operation; thus, the ERP system
that supports the daily business also has to trend
towards knowledge-based management, commu-
nication, and operation.
Wireless: Access to the ERP system from a mobile
device.
Currently, there are two methods to secure an
ERP system: access control and logging. Many
companies will fail in their ERP security efforts
because the security control design and imple-
mentation are costly and time-consuming. The
stringent security control makes the operation
become more complex, so employees will not be
glad to see that. Within a large enterprise, there
will be many activities regarding the change of an
employee’s authorization level, such as promotion,
reassignment, or termination. This will make the
user-based access control very hard to implement,
and the administrator will always feel exhausted
dealing with these issues. More detailed logging
system will bring high cost and low performance
to the system, since it will have to trace every
?
?
?
?
event and log everything in detail. Therefore, users
will not be glad. As the ERP becomes more Web-
based, the security issue within an open system
becomes critical.
Usually, better security solutions will bring higher
cost and lower performance to a system. This con-
tradiction always exists in any type of system. ERP
is the system used to lower the cost and increase
the pro?t of an enterprise; hence, management will
consider the performance of the system ?rst and
foremost. For example, assuming solution A and
B, solution A provides better security control than
B. It is not de?nite that A will perform better than
B in the real case. The key factor is whether A
will bring much more cost to the system than B.
The psychological factor of the users should also
be considered. The solution should be amended
based on its cost and impact to the performance of
the system; otherwise, it may not be acceptable for
the enterprises.
Policies
Much of the focus on ERP security has been on
con?dentiality (Thuraisingham, 2005). However,
we need to include other types of policies. These
include the following:
Need-to-know policies: These are policies where
access is granted based on whether a user needs
to know. These policies are enforced in military
environments.
Need-to-share policies: There is now a migration
from need-to-know to need-to-share policies in
many organizations, including the military. Finan-
cial and healthcare operations also have to share
data to carry out their operations. We discuss
need-to-share policies in our paper on Assured
Information Sharing (Thuraisingham, 2006).
Trust policies: These policies ensure that data are
shared only between individual organizations that
are trusted.
Integrity policies: These policies ensure that data
are modi?ed by authorized individuals. Further-
more, data quality and provenance policies that
determine where the data have traveled and the
accuracy of the data may also be included under
the integrity policies.
?
?
?
?
She and Thuraisingham 162
Essentially an ERP system has to enforce the vari-
ous policies. However, not all of these policies are
needed for all applications. Therefore, one needs to
examine the application, determine the policies that
are relevant, and develop ways to enforce them.
Secure Content and
Knowledge Sharing
The exchanging infrastructure sets up the cor-
nerstone for an ERP system; effective coordination
becomes a stringent requirement that needs to be
ful?lled in today’s ERP system. Therefore, securing
the exchanged document is the cornerstone for ERP
security; appropriate schema integrating encryption
and digital signature technologies into XML frame-
work is necessary to achieve this goal. Furthermore,
appropriate security architecture or model has to be
designed so as to support sharing the knowledge
in an open and multi-organizational environment.
Much work has been done in this area, such as trust
management and the UCON model, although these
security frameworks have not yet been applied in
most commercial ERP products. As we mentioned
earlier, the cost and return must be evaluated before
implementing such technologies.
Web Services Security
As we mentioned in the “ERP Technology” sec-
tion, Web services and service-oriented architectures
are key technologies for ERP systems. Therefore,
securing Web services and service-oriented archi-
tectures are needed.
Various efforts have been reported on securing
Web services (Bertino et al., 2004). Furthermore,
standards such as OASIS have developed security
speci?cations including SAML (Security Assertion
Markup Language) and XACML (XML Access Con-
trol Markup Language) (OASIS Security Speci?ca-
tions, 2003). In addition, securing XML documents
as well as securing semantic Web technologies have
received attention (Bertino et al., 2004; Thurais-
ingham, 2005). Program such as the Department
of Defense Global Information Grid have focused
on security for service-oriented architectures GIG/
IA National Security Agency Presentation, 2005).
However, little work has been reported on adapting
the various technologies for securing ERP. This will
be the major challenge.
CONCLUSION
Enterprise Resource Planning is the technology
that drives the reformation in the realm of economy
and impacts people’s life style indirectly. ERP sys-
tem now is going towards a system with more coor-
dination/collaboration, higher heterogeneity and
integrity, more intelligent, operating on the level of
knowledge, and even wireless-enabled. The security
issue within ERP has been there for a long time, but
most of the solutions are based on the assumption
that an ERP system is a closed environment. Given
current trends, where the ERP is more likely to be an
open system, these solutions are insuf?cient to pro-
vide the security. Although there are many research-
ers working in this area and some solutions are
provided to better suite the open environment, yet
the security mechanism for ERP system has not yet
been brought to the open environment for discus-
sion. Furthermore, these existing security solutions
are based on the features of the current ERP system;
since ERP reveals more and more new features that
may be supported in the future, the security mecha-
nism has to be retro?tted and new security issues
have to be identi?ed. The research should focus on
the following areas:
Policy, model and design of the security architec-
ture.
Securing the exchanged documents.
Securing the management and sharing of knowl-
edge .
Securing web services and service oriented
architecture.
User authentication and authorization methods in
open environment.
Securing data transfer in wired and wireless com-
munications, especially security issues on low
power devices.
Examining the security of the interfaces between
different components (e.g., operating system, data-
base system, and logging mechanism) and ensur-
ing that no security loopholes are introduced due
to component interactions.
?
?
?
?
?
?
?
163 Security for Enterprise Resource Planning Systems
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doc_540185508.pdf
Enterprise Resource Planning (ERP) is the technology that provides the unified business function to the organization by integrating the core processes. ERP now is experiencing the transformation that will make it highly integrated, more intelligent, more collaborative, web-enabled, and even wireless.
152
ABSTRACT Enterprise Resource Planning (ERP) is the technology that
provides the uni?ed business function to the organization by integrating the
core processes. ERP now is experiencing the transformation that will make
it highly integrated, more intelligent, more collaborative, web-enabled, and
even wireless. The ERP system is becoming the system with high vulnerabil-
ity and high con?dentiality in which the security is critical for it to operate.
Many ERP vendors have already integrated their security solution, which may
work well internally; while in an open environment, we need new technical
approaches to secure an ERP system. This paper introduces ERP technology
from its evolution through architecture to its products. The security solution
in ERP as well as directions for secure ERP systems is presented.
KEYWORDS authorization, Enterprise Resource Planning,
exchange infrastructure, policies, RBAC, Web services
INTRODUCTION
Enterprise Resource Planning, a business integration approach, has been
widely deployed in various kinds of organizations since it was ?rst de?ned
by the Gartner Group in 1990 as the next generation of Manufacturing Busi-
ness System and Manufacturing Resource Planning software. Today, ERP is
considered to be “the price of entry for running a business” (Kumar and van
Hillegersberg, 2000).
An ERP system is an integrated, con?gurable, and tailorable information
system which plans and manages all the resources and their use in the enter-
prise, and streamlines and incorporates the business processes within and
across the functional or technical boundaries in the organization. With ERP,
an enterprise can automate its fundamental business applications, reduce
the complexity and the cost of the collaboration, force the enterprise itself
to take part in the Business Process Reengineering (BPR) to optimize its
operations, and ?nally result in a successful business.
The objective of this paper is to give an overview of the state of the art
in ERP technology and the security issues for an ERP system. In particular,
Address correspondence to the authors
at [email protected] or
[email protected]
Address correspondence to the authors
at [email protected] or
[email protected]
Security for Enterprise
Resource Planning Systems
Wei She and
Bhavani Thuraisingham
University of Texas at Dallas,
Richardson, TX, USA
Information Systems Security, 16:152–163, 2007
Copyright © Taylor & Francis Group, LLC
ISSN: 1065-898X print/1934-869X online
DOI: 10.1080/10658980701401959
153 Security for Enterprise Resource Planning Systems
we discuss the evolution of ERP, its key compo-
nents, the status of vendor products, and what has
been done with respect to security. Our research as
well as plans for secure ERP systems will also be
discussed.
The organization of this paper is as follows. The
history and evolution of ERP systems will be given
in the next section. ERP technologies and frame-
work including the communication platform such
as EDI, ALE, and Exchange Infrastructure are pre-
sented in the “ERP Technology” section. This section
also includes a discussion of the ERP architecture,
some aspects of SAP, and the emerging web ser-
vices for ERP. Major ERP vendors and their products
are discussed in the “Vendors and Products” section.
Security issues for ERP systems are discussed in the
following section, “Security in ERP.” In particular,
the overview of the ERP security using a layered
approach, as well as the RBAC model for ERP is dis-
cussed. We will compare these security features with
the authorization function in SAP R/3 system and
the Baan security solution. Some of our researches
in ERP as well as trends are discussed.
HISTORY OF ERP SYSTEMS
AND APPLICATIONS
The history of ERP traces back to the 1960s, when
most organizations were developing the centralized
computing systems using Inventory Control Pack-
ages (IC) in order to automatically manage a com-
pany’s inventories. These legacy systems are mostly
based on programming languages such as COBOL
and FORTRAN. In the 1970s, Material Requirements
Planning (MRP) systems were developed to man-
age the requirements and plan production. Later,
Manufacturing Resources Planning (MRP II) system
emerged in the 1980s, aiming to optimize the manu-
facturing process. The concept of ERP was intro-
duced in the early 1990s as an enterprise-wide and
across-functional integration of the core organiza-
tional business processes, including manufacturing,
distribution, accounting, ?nancial, human resource
management, project management, inventory man-
agement, service and maintenance, and so on. From
the point of views of some researchers, the ERP
technology after 2000 is considered as “Extended
ERP” (Rashid, Hossain, and Patrick, 2002) because
e-business solutions such as Customer Relationship
Management (CRM) and Supply Chain Management
(SCM) are included into the core modules of original
ERP systems.
ERP has a wide range of applications in both
industrial and non-industrial areas such as aerospace
and defense, banking, consumer products, construc-
tion, healthcare, education and research, insurance,
raw and processed materials, logistics, transporta-
tion, wholesale, public sectors, telecommunication,
and so on. In the early years after ERP emerged,
deploying and maintaining an ERP system was
expensive and took a relatively long time to recover
costs. Since then, the implementation and mainte-
nance cost of ERP system was greatly reduced due
to the retro?t of technical infrastructure. Nowadays,
many light-weight ERP applications are developed
for small and medium companies.
Various commercial products, including SAP, Ora-
cle, and Baan, are now available in the marketplace.
Furthermore, Web services and service-oriented
architectures are the major underlying technologies
for emerging ERP systems.
ERP TECHNOLOGY
Overview
ERP systems have evolved extensively over the
years. Initially, such systems were used for simple
functions such as accounting and human resources
planning. With the advent of Web technologies,
companies such as Oracle, SAP, and Baan began
developing a suite of applications for ERP systems.
The emerging technologies such as Web service
and eXtensible Markup Language (XML) have had a
major impact on ERP systems.
In this section, we discuss the various compo-
nents of ERP systems. We start with a discussion
of its architecture and various business components
in the next section including ?nancial management,
human resource management, production lifecycle
management, customer relationship management,
and manufacturing management. In the “EDI, XML,
and Information Exchange” section, we discuss
exchange infrastructure, the cornerstone of ERP sys-
tems. In this section, we also discuss the two tech-
nologies for exchanging electronic documents among
She and Thuraisingham 154
different entities: EDI and XML. Finally, emerging
Web services and their relationship to ERP systems
are discussed in the ?nal section, “Web Services.”
ERP Architecture
There are many disadvantages to MRP II and MRP
technologies. In an enterprise, some systems may
be developed by the enterprise itself, while others
may be developed by different vendors using differ-
ent databases, languages, and technologies. Systems
differ from each other, which makes it dif?cult to
upgrade the organization’s businesses, strategy, and
information technologies effectively. With the com-
munication infrastructure and ERP functionalities
encapsulated in components, an ERP system can
easily meet these requirements. A typical ERP sys-
tem should at least have the following features:
Componentized—different business functional-
ities are designed as different components.
Integrated—components are integrated and seam-
less data ?ow between components allows them
to collaborate as a one function.
Flexible—system is expandable and compatible
with the old systems, the change to the business
processes and strategies are easy to ful?ll (Glass,
1998).
Tailorable—system should be easily con?gured
according to the enterprise’s needs.
Real-time—the components work in real time,
online, and batch processing modes should be
available.
Pro?table—system must have the potential to
reduce the cost or increase pro?t, since these are
a company’s basic requirements and motivations.
Secured—security schema has to be enforced to
protect various enterprise resources regardless
whether it is appropriate or suf?cient.
The business logic in ERP system employs client/
server architecture to create a distributed computing
environment. Generally, the three-tier architecture
will be used, which contains three layers of logic:
1. Presentation Layer (Front): A uni?ed Graphi-
cal User Interface (GUI) or browser that collects
input, generates requests, and returns the results
back to the user.
?
?
?
?
?
?
?
2. Application Layer (Middle): Application programs
that collect the requests from the Presentation
layer and process the requests based on the busi-
ness rules, functions, or logics.
3. Database Layer (Back): DBMS that manages the
operational and business data throughout the
whole enterprise and the user access to this infor-
mation. This layer may also include the operating
system and the related hardware (Sprott, 2000),
since they are necessary for the system but trans-
parent to users.
As the basis of the ERP system, an information
exchange platform such as SAP NetWeaver will
always be deployed before implementing ERP soft-
ware. After consolidating the business logic and the
technical platform, we will have the ERP system
architecture as showed in Figure 1.
The components that different ERP vendors
provide may vary, as they will always have some
inclines due to the historical problems, yet the core
functionalities are nearly the same. These function-
alities include (Bakry and Bakry, 2005; Shehab et
al., 2004):
Financial Management, which may includes the
functionalities such as collection and payment
management, payables and receivables manage-
ment, assets and properties management, cash
management, loans, ?nancial consolidation, gen-
eral ledger, treasury management, and planning
and budgeting.
Human Resource Management, which may have
the functionalities such as payroll management,
self-service, learning management, bene?ts,
recruitment, tutor, timer and labor management,
and compensation management.
?
?
Da t a ba s e
L a y e r
R
D
B
M
S
Graphi cal User I nterface
Exchange I nfrastructure
F I N B I P L M C R M S C M S R M H R Lega c y
Pr es ent at i on
L a y e r
Appl i c at i on
L a y e r
Communi cat i on
Pl a t f or m
FIGURE 1 The Architecture of Enterprise Resource Planning
155 Security for Enterprise Resource Planning Systems
Manufacturing Management, which will provide
the functions such as discrete manufacturing, pro-
cess manufacturing, ?ow manufacturing, manufac-
turing scheduling, and shop ?oor management.
Sales, Distribution, and Logistics Management,
which includes the functions as order capture, ser-
vices, sales, sales incentive management, pricing,
logistics, bulk stock management, inventory man-
agement, warehouse management, requirements
management, and strategic account planning.
Customer Relationship Management (CRM), which
maintains the relationships between the organi-
zation and its customers and includes function-
alities such as collecting, storing, and analyzing
customer information.
Product Lifecycle Management, which manages
the entire lifecycle of a product from conception
and design to manufacture, service, and disposal.
Supplier Relationship Management (SRM), similar
to CRM which deals with customers, SRM man-
ages the supplier relationships by collecting, stor-
ing, and analyzing supplier information.
Business Intelligence, whose concept has a wide
range covering all the processes performing anal-
ysis and/or evaluation which either work at the
strategy level, tactical level, or operational level
by providing instruction for optimizing business
performance. Demand management can be clas-
si?ed into this category.
Supply Chain Management (SCM), which is another
concept having some overlap with above compo-
nents. An SCM can include the business processes
such as CRM, SRM, manufacturing management,
demand management, and production planning.
The key point is that these business processes
have to be connected across organizations in order
for a business success of supply chain. These pro-
cesses are inter-organizational, thus may be either
included in or excluded from the scope of ERP.
With the de?nition of extended ERP, we no longer
consider ERP as internal within an organization.
The scope of the term “ERP” is a bit confusing
when comparing it to the term “e-commerce.” Gen-
erally speaking, ERP is more concerned with the
internal functionalities in an organization; on the
other hand, e-commerce or e-business focuses on
the business across companies. While under current
global business strategy, companies are no longer
?
?
?
?
?
?
?
competing with each other as individuals, coordi-
nation enables several companies to compete as a
whole. SCM literature discusses much in this area,
and people are considering a supply chain as the
competition unit. With coordination, we cannot
always assume that some components are working
internally and some others are working externally.
Thus, the boundary between ERP and e-commerce
is blurred in many cases; and it is inappropriate and
unnecessary to discuss the technical issues from the
narrow concept of ERP (internal).
EDI, XML, and
Information Exchange
Electronic Data Interchange (EDI), also called
“paperless exchange” (Nagpal, de Bruyn and Lyfareff,
1999), is the technology that allows enterprises to
exchange business information between separate
computer systems, using a standard structured for-
mat (ANSI ASC X.12 in the late 1970s and EDIFACT
in the 1980s) over a communication network. EDI
technologies such as SAP’s exchange infrastructure
(White Paper, SAP Exchange Infrastructure 2.0, 2002;
White Paper, SAP R/3 Enterprise, 2002; White Paper,
SAP Exchange Infrastructure 2.0 Technical Infrastruc-
ture, 2002) have been in place for many years as the
footstone of all ERP technologies. Although those
systems implementing EDI exchanging documents
have become legacy systems today, the major contri-
bution from EDI technology, the business semantics,
is preserved by combining EDI and XML.
XML (W3C, 2006) is a ?exible text format standard
developed by the World Wide Web Consortium (W3C).
It is a simpli?cation of Standard Generalized Markup
Language (SGML) for originally large-scale electronic
publishing and later as the standard for exchanging
various data over the Web. The major advantage of
XML over other description languages (e.g., HTML)
is its ability to represent the data format using Docu-
ment Type Declaration (DTD) schema or XML schema
(W3C, XML Schema Part 0, 2004; W3C, XML Schema
Part 1, 2004; W3C, XML Schema Part 2, 2004). This is
the reason XML is applied in many ERP applications
developed in recent years. XML-based document
exchange removes the obstacle faced by most small
and medium organizations—high implementation
and maintenance costs of exchanging infrastructure
She and Thuraisingham 156
(Iacovou, Benbasat, and Dexter, 1995). Frameworks
such as xCBL (Common Business Library) and lan-
guages such as ebXML (OASIS, 2001; OASIS, 2006)
were designed in recent years to support enterprise-
wide applications by combining the business seman-
tics of EDI technology and the ?exible and innovative
data model of XML. Furthermore, a new trend among
organization management is towards knowledge-
based management, which means that resources lying
within an ERP system are now viewed as knowledge
instead of information or data. This trend starts by
distinguishing among three concepts: data, informa-
tion, and knowledge. Data are simply raw numbers or
facts, information is processed data, and knowledge is
information processed in the mind of a person. Thus,
knowledge may have more various representations
that must be supported by the description languages.
This is another reason exchanging infrastructure now
becomes XML-based.
Web Services
Thuraisingham (2006) stated that we are now in
the third wave of ERP systems. The ?rst wave related
to manufacturing applications; the second was spe-
cialized applications such as supply chain manage-
ment; and the third was based on Web services.
The use of Web services eases integration and
also reduces costs. Clients want to access informa-
tion without having to go through ERP software.
Therefore, with the use of Web services and the
composition of Web services, clients as well as
outsourcing vendors can access many of the ERP
applications seamlessly. These applications include
checking bank accounts, placing orders, and other
services. Reduction in cost comes from the fact that
clients can communicate with legacy ERP software
through Web services and do not have to deal with
the complexities of the software. Also ERP vendors
are introducing the Web scenarios broker hub that
will act as a broker between Web services and the
ERP software. SAP offers this hub through mySAP
and Oracle via its e-business suite.
VENDORS AND PRODUCTS
In this section, we provide an overview of the
major ERP systems vendors. SAP is one of the most
prominent vendors of ERP. Other vendors include
PeopleSoft and Baan. However, PeopleSoft has been
purchased by Oracle, and Oracle is emerging as
a major ERP systems vendor. Furthermore, Oracle
provides the server technologies that ERP appli-
cations could utilize, while SAP and Baan rely on
various vendor products for server technologies. We
will provide an overall discussion about the prod-
ucts provided by SAP, Baan and Oracle. Note that
Baan has been purchased by SSA. Microsoft is also
becoming a major player in ERP software.
SAP ( Systems, Applications, and Products
in Data Processing ) was formed in 1972 by ?ve
former IBM employees in Germany. SAP focuses on
the development of application software for real-
time business processing, beginning with its ?rst
accounting software developed in 1973. Its ?rst ERP
product, SAP R/2, was developed in the late 1970s
using a centralized database and dialog control sys-
tem. In the 1990s, SAP R/3, which uses the three-tier
architecture of database, application, and user inter-
face, was unleashed on the market. R/3 was a break-
through, making SAP the largest vendor in the ERP
market by 1999. By 2005, there were around 100,000
installations worldwide, more than 1500 partners,
over 25 industry-speci?c business solutions, and
more than 30,000 customers in over 100 countries.
SAP now owns 26% of CRM market share, 29% of
ERP market share, and 19% of SCM market share
by total software revenue. SAP NetWeaver uni?es
the integration technologies into a single platform,
which lays the groundwork for the integration all
systems SAP runs or non-SAP software. It is the basis
of SAP ERP applications, partner solutions, and cus-
tom-built applications. SAP R/3 is the third genera-
tion set of highly integrated software that performs
the core business functions within a company; while
mySAP, which also includes R/3 component as an
important building block, is intended to empower
the collaboration between organizations. mySAP is a
Web-based e-business suite.
Oracle, which was founded in the 1970s in
the USA, is most famous for its well-known rela-
tional database Oracle and is the second-largest soft-
ware company in the world. In 1987, Oracle offered
its ?rst ERP software—Oracle General Ledger. In the
following years, Oracle developed other ERP soft-
ware such as self-service applications, strategic pro-
curement solution, ?nancial consolidation engine,
157 Security for Enterprise Resource Planning Systems
and ?ow manufacturing product. Oracle’s ERP sys-
tem is now known as Oracle E-business Suite, which
has more than 50 different modules covering the fol-
lowing areas: ?nance, accounting, human resources,
manufacturing, supply chain management, project,
and front of?ce. Oracle also has many other well-
known products in other ?elds such as database,
data warehousing, and work?ow. After the acquisi-
tion of PeopleSoft and JD Edwards in 2004, Oracle
gained approximately 22% of the ERP market share.
PeopleSoft Enterprise is the business application
suite that offers Web services integration with multi-
vendor and homegrown applications; it is admittedly
considered easier to con?gure and more ?exible than
its competitors. JD Edwards EnterpriseOne and JD
Edwards World are both the business applications
from J.D. Edwards Company, which has extensive
experience supplying software for the IBM iSeries
platform. JD Edwards World provides the Web-
enabled applications for the management of plants,
inventories, equipments, ?nances, and people.
Sage, founded in England in 1981, entered
the ERP market and gained a solid market share
using the strategy of acquiring small ERP vendors
such as Tetra and Interact Commerce Inc. By 2005,
Sage had revenue of $1.4 billion in the ERP mar-
ket and claimed 6% market share as the third-largest
ERP vendor. Sage Line 500 v6 is newest version of
the Sage Line 500 product family, which is the Web-
based integrated ERP solution covering core func-
tionalities in a company. Sage 1000 is new, single
business management software designed to offer the
operations within mid-size organizations.
Microsoft, founded in 1975, is the biggest
software company in the world with its famous
Windows series products. Microsoft Business Solu-
tion Group (MBS) is the department that focuses on
providing ERP solutions, such as Microsoft Dynam-
ics (formerly Microsoft Business Solutions), which is
the integrated business management solution that
includes ?nancials, customer relationship manage-
ment, and supply chain management. By 2004, MBS
had revenue of around $800 million, giving it a 4%
ERP market share.
Others. In addition to the major vendors, there
are several other ERP vendors that are emerging. In
2004, the biggest ERP vendors—SAP, Oracle, Sage,
Microsoft, and SSA—accounted for around 70% of
ERP market share by revenue. The other 30% was
shared by other ERP vendors such as Geac, Intentia,
Infor Global Solutions, and Lawson.
SECURITY IN ERP
Overview
Security is critical for ERP systems, as they are
used in numerous industries including defense,
intelligence, medical, and ?nancial. First, we need
to develop a security policy and a model for ERP
systems. Many of the current systems focus on con-
?dentiality aspects of security. In this section, we
discuss the developments as well as current trends
in security for ERP systems.
In the “Approaches to Security” section, we dis-
cuss what needs to be secured. In section “Cur-
rent Solutions,” we discuss current developments,
including security, for SAP. In the “Next-Generation
Models” section, we discuss some of the next-gen-
eration security models. In the concluding section
“Directions on ERP Security,” we provide an over-
view of trends, including a discussion of security
policies and Web services security.
Approaches to Security
Security problems exist in every facet of an ERP
system. These facets can be classi?ed into three cat-
egories: network layer, presentation layer, and appli-
cation layer, which includes business processes,
internal interfaces, and database.
When a customer/partner communicates with an
ERP system, or the business components located in
different places interact with each other, the secu-
rity problems in these cases are classi?ed into the
network security domain. ERP experts will not deal
with these cases directly, instead this function will
be provided by purchasing from other vendors who
are experts at network security.
The presentation layer refers to the graphical user
interface, browsers, and PCs. Since the transmission
of GUI packets is impossible to restrict, ERP experts
cannot secure the system by limiting user access to
GUI. The better way to provide security may be to
place a CITRIX server between the user and the ERP
system.
She and Thuraisingham 158
The security in application layer invests large
efforts of the ERP experts to offer an effective way
to secure the business data and processes. The
technicians will also choose to activate/deactivate
the security functions provided by the database ven-
dor according to the overall security solution. Van de
Riet, Janssen, and Gruijter (1998) summarized some
of the security aspects in an ERP system:
Security policy and administrator: ERP experts
have to provide such a way that explicit and well-
de?ned security policies can be easily de?ned
and maintained. The security policies will offer
the rules for the access of subject to object, and
these are the constraints put on the administra-
tors when they are granting/denying permissions
to the users.
User authentication: to verify whether the user is
the same person as he claims.
Separation of duties: tasks must be classi?ed such
that certain tasks can only be performed by cer-
tain users or roles.
Authorization: to verify whether the user has
access to the relevant resources. Depending
on the authorization rules, the user is granted
access.
Time restriction: the access is permissible only
during certain time.
Log and trace: the logging and tracing of relevant
events has to be done with preventing the log
?les from breach.
Database security.
Essentially we need end-to-end security for ERP
systems. The next three sections discuss some of the
current trends and directions for secure ERP.
Current Solutions
Role-Based Access Control
Many of the current systems are based on Role-
Based Access Control (RBAC), although they may
have different settings of either enhancements (Kern
et al., 2002) or simpli?cations. This model (Figure 2)
de?nes roles and grants certain access rights. Accord-
ing to Sandhu et al. (1996), an RBAC model consists
of the following components:
?
?
?
?
?
?
?
Permissions: Permission is the access to one or
more objects in the system. The permission has
different meanings in different environment. If in
a database system, the permission refers to the
rights such as select, update, delete, or insert a
record. If an accounting application, it may be the
rights such as account creation/deletion, credit/
debit, and transfer (Sandhu et al., 1996).
Roles: A role is a named job function within the
organization. A role may be hierarchical. For
example, an engineer role is also an employee
role.
Users: A user is a person who may be assigned
one or more roles.
Constraints: In the system where there is only
one single administrator, the constraints may be
meaningless. If the administration is decentral-
ized, meaning there are several administrators,
the constraints will be used by the senior admin-
istrator to restrict the junior administrator’s right
to grant/deny the permissions.
Authorization in SAP R/3
Some of the concepts involved in the authori-
zation in SAP R/3 system are listed below (White
Paper, Authorization Made Easy, 2000; Goodman,
2004; Schaad, 2006):
Authorization object, which represents the autho-
rization concept and consists of some authoriza-
tion ?elds.
Authorization, which is an instance of one autho-
rization object and de?nes the permitted value
range of each authorization ?eld of the authoriza-
tion object.
?
?
?
?
?
?
Role User
Permi-
ssion
Session
Constraint
User-to-role
Assignment
Role-to-permission
Assignment
Role-
Hierarchy
FIGURE 2 The Model of Role-based Access Control [6]
159 Security for Enterprise Resource Planning Systems
Authorization pro?le, which contains some autho-
rizations which are assigned to the user by the
administrator.
Authorization check, which is used to protect the
transactions or data you choose and is embed-
ded in the program logic. When the authorization
check is performed, the authorization pro?le will
be used to compare the required values to run the
speci?c transaction.
User master record, which enables the users to
log on to the R/3 system and grant limited access
to the transactions and data.
Pro?le generator is the component which helps the
administrators create, generate, and assign autho-
rization pro?les using activity groups and user.
A pro?le generator may have the following
components:
Activity group is a collection of activities such as
tasks, reports and transactions. An activity group
usually represents a job in the enterprise. An
activity group can have many users assigned to it,
and a user can also be assigned to many activity
groups. An activity group can be assigned to the
following types of users: user ID, job, and position.
Job represents the general classi?cation of duties.
Position represents a person’s detailed individual
assignment within an enterprise. The difference
between job and position is that job is just the title
which does not imply what projects you will do in
the company, while position does so.
Composite activity group is the collection of sev-
eral activity groups.
User assignment is the task that assigns one or
more users/roles/positions to one or more activity
groups or composite activity groups.
Another important concept in the authorization
in R/3 is authorization administration, which means
whether the creation, generation, or assignment of
authorization is centralized or decentralized (one or
more administrators).
Through these concepts, we may learn that
the mechanism of R/3 authorization is actually an
instance of Role-Based Access Control Model, except
that it contains some elements speci?cally used in
R/3 environment. Figure 3 provides a visual under-
standing of the model of authorization in R/3 system.
?
?
?
?
?
?
?
Furthermore, Logging and Tracing is also a required
component to secure the application layer of ERP
system, although it is not the key function.
Baan Security using DEM
In Baan (bought by SSA) security architecture
(Valente, 1999), we can easily determine if the solu-
tion is based on the RBAC model. Baan security solu-
tion uses a tool called Dynamic Enterprise Modeler
(DEM) to assist the security con?guration of Baan.
DEM is used to model business processes or func-
tions of an organization and de?ne the roles. Within
the architecture of Baan’s security solution, there are
four concepts: User Employee, Role, and Process.
User: Baan user is the pro?le including all of an
employee’s personal information.
Employee: The person who works in the
organization.
Role: De?ned to indicate the position and the
assignments of the employee. All employees must
be assigned to a role, and roles will be assigned
to the business processes.
Process: Once a process is modeled in Baan ERP,
roles will be attached to that process.
Next-Generation Models
Extended RBAC
Most contemporary ERP software adopts tradi-
tional access control methods such as RBAC as its
?
?
?
?
Auth.
Field
Auth.
Field
Auth.
Field
Au t h .
Obj ect
Auth.
Value
Auth.
Value
Auth.
Value
Aut hor i -
zat i on
Pr of i l e
Auth.
Profile
Auth.
Profile
Auth.
Profile
Us er
User
Role
Positio
n
Pr of i l e
Gener at or
Act. Group
FIGURE 3 The Model of Authorization in r/3
She and Thuraisingham 160
primary measure to secure the system. What these
methods care is whether some subject is allowed to
perform the requested rights on the object. In some
cases, the subject has to meet mandatory require-
ments before exercising the rights. A good exam-
ple is that the researchers have to ?ll up his/her
personal information before he can have the rights
to read or download white papers. This mandatory
requirement is Obligation (Park and Sandhu, 2004).
Another important requirement for accessing the
resources is the environmental or system require-
ment called Condition (Park and Sandhu, 2004), such
as accessing time, date, and location. Since these
functional predicates are not included in the idea of
traditional access control methods, a straightforward
enhancement of RBAC today is to introduce obliga-
tion and condition predicates. So we have so-called
Extended-RBAC.
In this ERBAC model, an extra decision manager
is added since obligation and condition predicates
will be taken into account. In the decision process,
condition requirements will be checked ?rst; if all the
environmental conditions are met, the checking pro-
cedure for the obligations will be triggered; and, at
last, the decision process will check whether the user
is intended to access the information. Srinivasan and
Thuraisingham are examining the extended RBAC
model for ERP (Srinivasan and Thuraisingham, 2006).
UCON
In recent years, a new model, Usage Control
Model (UCON), was proposed in order to set up
a framework for the future security techniques in
ERP. UCON not only integrates three functional
predicates (authorization, obligation, and condition)
but also brings in the concept of time. This feature
allows a security component in ERP system to be far
more dynamic (Park and Sandhu, 2004).
The UCON model consists of the following core
components:
Subject and subject attributes: An entity with asso-
ciated attributes which holds or exercises some
certain rights on objects.
Object and object attributes: An entity with asso-
ciated attributes which one or several subjects
hold or exercise rights on.
?
?
Rights: Privileges that a subject can or cannot
access an object.
Authorization: Functional predicate determining
whether a subject is allowed to perform some
right on an object.
Obligation: Functional predicate verifying
whether the mandatory requirements have been
ful?lled before a subject performs some right on
an object.
Condition: Functional predicate that checks whether
the current environmental or system status allows
a subject to perform some right on an object.
The UCON model is a large model family in
which different combinations can exist for the
three predicates. If we regard the UCON mod-
els with only one of these predicates used as the
leaf nodes, we can build a tree rooted at UCO-
N
ABC
model. We denote these models as UCON
A
,
UCON
B
, and UCON
C
. These models can be broken
into several submodels based on whether time is
taken into consideration. For example, UCON
A
will
be divided into UCON
preA
and UCON
onA
. Further-
more, these submodels can be divided into more
detailed models depending on when and whether
the update of mutable attributes will occur. We are
currently investigating the applicability of UCON
features for ERP security.
DIRECTIONS ON ERP SECURITY
Trends
Looking into the history of ERP technology, it is
easy to ?nd that the transformation from mainframe
structure into client/server architecture is its big-
gest step. With this architecture, it became possible
to develop a large system which integrates lots of
functionalities. Now, ERP becomes the core of the
operation and business in a company. ERP will not
always remain the same as the requirement of auto-
mation of business evolves. The future ERP system
may have the following features:
Heterogeneous: Heterogeneous/heterogeneity
means that the components from different ven-
dors coexist and cooperate in an ERP system.
It has two prerequisites: componentization and
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161 Security for Enterprise Resource Planning Systems
integration. It is true that some of the leading
ERP vendors are going to or have already done
something regarding these two aspects. Stronger
communication platforms are provided to support
heterogeneous applications, and applications are
developed in the form of components.
Collaborative (Jayaweera, Johannesson and
Wohed, 2001): This could be in the realm of e-
business. We can classify the business processes
within an enterprise into two types: enterprise-
centric process and collaborative process. Pro-
cesses such as accounting and payroll processing
are enterprise-centric; others such as supply chain
management are almost completely collaborative.
There are some intervenient processes, yet they
are designed and developed in an enterprise-cen-
tric way. In the future, more processes will be
redesigned in a collaborative way. This feature
also implies the ERP system will be more open
and more Internet-based.
Intelligent: ERP system in the future will include
more components that do the analysis, investiga-
tion, or even advice on the strategic transform.
This feature implies that more con?dential infor-
mation will ?ow within or out of an ERP system.
Knowledge-based: Firms are moving towards
knowledge-based operation; thus, the ERP system
that supports the daily business also has to trend
towards knowledge-based management, commu-
nication, and operation.
Wireless: Access to the ERP system from a mobile
device.
Currently, there are two methods to secure an
ERP system: access control and logging. Many
companies will fail in their ERP security efforts
because the security control design and imple-
mentation are costly and time-consuming. The
stringent security control makes the operation
become more complex, so employees will not be
glad to see that. Within a large enterprise, there
will be many activities regarding the change of an
employee’s authorization level, such as promotion,
reassignment, or termination. This will make the
user-based access control very hard to implement,
and the administrator will always feel exhausted
dealing with these issues. More detailed logging
system will bring high cost and low performance
to the system, since it will have to trace every
?
?
?
?
event and log everything in detail. Therefore, users
will not be glad. As the ERP becomes more Web-
based, the security issue within an open system
becomes critical.
Usually, better security solutions will bring higher
cost and lower performance to a system. This con-
tradiction always exists in any type of system. ERP
is the system used to lower the cost and increase
the pro?t of an enterprise; hence, management will
consider the performance of the system ?rst and
foremost. For example, assuming solution A and
B, solution A provides better security control than
B. It is not de?nite that A will perform better than
B in the real case. The key factor is whether A
will bring much more cost to the system than B.
The psychological factor of the users should also
be considered. The solution should be amended
based on its cost and impact to the performance of
the system; otherwise, it may not be acceptable for
the enterprises.
Policies
Much of the focus on ERP security has been on
con?dentiality (Thuraisingham, 2005). However,
we need to include other types of policies. These
include the following:
Need-to-know policies: These are policies where
access is granted based on whether a user needs
to know. These policies are enforced in military
environments.
Need-to-share policies: There is now a migration
from need-to-know to need-to-share policies in
many organizations, including the military. Finan-
cial and healthcare operations also have to share
data to carry out their operations. We discuss
need-to-share policies in our paper on Assured
Information Sharing (Thuraisingham, 2006).
Trust policies: These policies ensure that data are
shared only between individual organizations that
are trusted.
Integrity policies: These policies ensure that data
are modi?ed by authorized individuals. Further-
more, data quality and provenance policies that
determine where the data have traveled and the
accuracy of the data may also be included under
the integrity policies.
?
?
?
?
She and Thuraisingham 162
Essentially an ERP system has to enforce the vari-
ous policies. However, not all of these policies are
needed for all applications. Therefore, one needs to
examine the application, determine the policies that
are relevant, and develop ways to enforce them.
Secure Content and
Knowledge Sharing
The exchanging infrastructure sets up the cor-
nerstone for an ERP system; effective coordination
becomes a stringent requirement that needs to be
ful?lled in today’s ERP system. Therefore, securing
the exchanged document is the cornerstone for ERP
security; appropriate schema integrating encryption
and digital signature technologies into XML frame-
work is necessary to achieve this goal. Furthermore,
appropriate security architecture or model has to be
designed so as to support sharing the knowledge
in an open and multi-organizational environment.
Much work has been done in this area, such as trust
management and the UCON model, although these
security frameworks have not yet been applied in
most commercial ERP products. As we mentioned
earlier, the cost and return must be evaluated before
implementing such technologies.
Web Services Security
As we mentioned in the “ERP Technology” sec-
tion, Web services and service-oriented architectures
are key technologies for ERP systems. Therefore,
securing Web services and service-oriented archi-
tectures are needed.
Various efforts have been reported on securing
Web services (Bertino et al., 2004). Furthermore,
standards such as OASIS have developed security
speci?cations including SAML (Security Assertion
Markup Language) and XACML (XML Access Con-
trol Markup Language) (OASIS Security Speci?ca-
tions, 2003). In addition, securing XML documents
as well as securing semantic Web technologies have
received attention (Bertino et al., 2004; Thurais-
ingham, 2005). Program such as the Department
of Defense Global Information Grid have focused
on security for service-oriented architectures GIG/
IA National Security Agency Presentation, 2005).
However, little work has been reported on adapting
the various technologies for securing ERP. This will
be the major challenge.
CONCLUSION
Enterprise Resource Planning is the technology
that drives the reformation in the realm of economy
and impacts people’s life style indirectly. ERP sys-
tem now is going towards a system with more coor-
dination/collaboration, higher heterogeneity and
integrity, more intelligent, operating on the level of
knowledge, and even wireless-enabled. The security
issue within ERP has been there for a long time, but
most of the solutions are based on the assumption
that an ERP system is a closed environment. Given
current trends, where the ERP is more likely to be an
open system, these solutions are insuf?cient to pro-
vide the security. Although there are many research-
ers working in this area and some solutions are
provided to better suite the open environment, yet
the security mechanism for ERP system has not yet
been brought to the open environment for discus-
sion. Furthermore, these existing security solutions
are based on the features of the current ERP system;
since ERP reveals more and more new features that
may be supported in the future, the security mecha-
nism has to be retro?tted and new security issues
have to be identi?ed. The research should focus on
the following areas:
Policy, model and design of the security architec-
ture.
Securing the exchanged documents.
Securing the management and sharing of knowl-
edge .
Securing web services and service oriented
architecture.
User authentication and authorization methods in
open environment.
Securing data transfer in wired and wireless com-
munications, especially security issues on low
power devices.
Examining the security of the interfaces between
different components (e.g., operating system, data-
base system, and logging mechanism) and ensur-
ing that no security loopholes are introduced due
to component interactions.
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163 Security for Enterprise Resource Planning Systems
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