why we need to integrate security in BPM

M. zur Muehlen and M. Indulska. Modeling languages for business processes and business rules: A representational analysis. Information Systems, 35(4):379–390, Elsevier, 2010.

 
Process modeling languages and security policies languages are both used to document organizational policies and procedures. While process modeling languages typically describe a procedural sequence of activities, including decisions and concurrency, security policy languages often rely on a declarative description of security conditions, and constraints that need to be followed. To date, their synergies and overlap are under researched. Understanding the relationship between the two languages types would allow organizations to maximize synergies, avoid content duplication, and thus reduce their overall effort.

G. Governatori. Law, logic and business processes. In Requirements Engineering and Law (RELAW), 2010 Third International Workshop on, pages 1 –10, sept. 2010.

S. Sadiq and G. Governatori, “Managing regulatory compliance in business processes,” in Handbook of Business Process Management, J. van Brocke and M. Rosemann, Eds.    Berlin: Springer, 2010, vol. 2, ch. 8, pp. 157–173.


Nowadays more and more businesses in all sectors relay and heavily depends on their process aware information systems. These systems are now essential to control, administer and enact all core business activities. Furthermore, failure to follow security policies is no longer an option. This means that research in business processes must now address the issue of how to incorporate techniques to handle security policies requirements, and these techniques should be conceptual, in the sense that they should provide notions and construction as close as possible to the concepts they intend to models. Until now ad-hoc solutions appear as the only option for otherwise routine situations. This leads to increased cost, and this is one of the reasons why security policies are still seen as burden on a process, instead of an opportunity to improve the performance of it.

S. Goedertier and J. Vanthienen. Designing compliant business processes with obligations and permissions. In J. Eder and S. Dustdar, editors, Business Process Management Workshops, volume 4103 of Lecture Notes in Computer Science, pages 5–14. Springer, 2006.

Business process languages such as UML Activity Diagrams, BPMN, Event- Process-Chains, etc. are most often based on the control-flow paradigm, and define an explicit order relation between the activities in the process. These order relations even occur in the case handling paradigm, in which a preferred or normal control-flow is defined between activities. What is lacking is a declarative approach that makes the partial order relations due to security and legal requirements more explicit.

what we need to enforce Sec. into BPM

G. Governatori. Law, logic and business processes. In Requirements Engineering and Law (RELAW), 2010 Third International Workshop on, pages 1 –10, sept. 2010.

It is a relationship between two set of specifications, where one the target does not result in violation of the source. This means that to determine whether a business process is appling the relevant security policies, one has to have:
1) a formal specification of the business process;
2) a formal specification of the (relevant) security policies;
3) a common framework to interface the two sets of specifications.
 

G. Governatori and Z. Milosevic. A formal analysis of a business contract language. Int. J. Cooperative Inf. Syst., 15(4):659–685, 2006.

A formal language for security policies should be conceptual, allowing its users to focus exclusively on aspects related to the content of the policy, ignoring implementation aspects.

Summary: Framework for Business Process and Rule Integration: A Case of BPMN and SBVR

R. Cheng, S. W. Sadiq, and M. Indulska. Framework for business process and rule integration: A case of bpmn and sbvr. In W. Abramowicz, editor, BIS, volume 87 of Lecture Notes in Business Information Processing, pages 13–24. Springer, 2011.

“Integrating the outputs of the two modeling approaches is a challenging task. First, business process models tend to be visual in nature. Business rules, however, tend to be text-oriented. Second, they have different composing elements. Third, they are designed for different purposes - process models describe how things should happen, whereas business rules describe what should happen. Finally, the overlap and inconsistencies between business process models and business rules also presents a significant challenge”. This paper is about a framework that integrates BPMN (Business Process Modeling Notation 2.0), process modeling language, and SBVR (Semantics of Business Vocabulary and Business Rules), rules modeling language.

Most available frameworks follow a top-down approach, and that integration should happen in the design stage, which is correct but not realistic. As in reality most organisations already have existing processes’ models and rules’ models that are separate, and the real problem facing organisations is integrating these existing models. That’s why a bottom-up approach is required, where integration happens in analysis stage. “The bottom-up integration framework is built around a collection of mapping methods that provide distinct ways in which overlap and consistency (or lack of) between processes and rules can be studied”.

Integration framework have two main aspects; semantic and structural aspects. Semantics aspects are about providing a reference that can provide a mapping between the two languages terms. Structural aspects are dealing with how the two languages have different structures. This paper only looked into structural aspects.

XML Process Definition Language (XPDL) was used as a canonical intermediate language to bridge the gap between BPMN, a visual process modeling approach, and SBVR, a text based business rule’s modeling language. Because, it is standardized and well supported, also it has the ability to transfer BPMN graphical notations into text representation.

To provide a mapping, both languages have to be broken down to the main components. SBVR was brought down to Name, Term, Verb, and four types of keywords. While BPMN consist of: activities, events, gateways, and participants. XPDL is used to translate each one of these BPMN components into XPDL tags and then mapped into SBVR component (a table is provided in the paper). The proposed approach do not have a way to present the model operation in BPMN except using ‘must’ or ‘it is obligatory’, which is considered a limitation of the solution. The paper also provided a car sale process and its business rules to demonstrate the proposed solution and prove its effectiveness.

in L.R.:

Cheng et al. in provided a bottom-up approach to integrate process models and business rules models in an analysis stage. There approach was specific to integrating BPMN process models with SBVR rules models. It used XPDL to translate the BPMN diagrams to text representation and then used these tags to map the business rules models, and finally producing a new model that include both the process and the rules. Even thought the approach was applied to BPMN and SBVR, but the idea can be generalized to other languages. A limitation to the approach, that it was only able to represent BPMN operations using either ‘must’ or ‘it is obligatory’. The approach did not invent a new language. It made use of XPDL and its ability to translate BPMN diagrams into XML tags. The main contribution was providing a list of the main components of the process language (BPMN) and the rules language (SBVR), and using XPDL to map these components to each other.

Challenges in integrating BP models and regulations

 

R. Cheng, S. W. Sadiq, and M. Indulska. Framework for business process and rule integration: A case of bpmn and sbvr. In W. Abramowicz, editor, BIS, volume 87 of Lecture Notes in Business Information Processing, pages 13–24. Springer, 2011.

"Integrating the outputs of the two modeling approaches is a challenging task. First, business process models tend to be visual in nature, with most of the relevant information represented graphically. Business rules, however, tend to be text-oriented. Thus, integration of the outputs of the two approaches requires an information exchange format with minimal information loss. Second, process models differ from business rules fundamentally as they have different composing elements. Third, they are designed for different purposes - process models describe how things should happen, whereas business rules describe what should happen. Finally, the overlap and inconsistencies between business process models and business rules also presents a significant challenge. In particular, a set of criteria is required that helps a business analyst to resolve identified overlaps and inconsistencies in a satisfactory manner."

Why do we need formal representation of Security policies

Resource: Wissam Mallouli, Fayc ̧al Bessayah, Ana R. Cavalli, and Azzedine Benameur. Security rules specification and analysis based on passive testing. In Proc. of the Global Communications Conference on Exhibition and Industry Forum Co-located with WTC (GLOBECOM’08), New Orleans, LA, USA, pages 2078–2083. IEEE, November-December 2008.

"A security policy is a set of rules that defines the desired behavior of users within an information system. Its main goal is to describe how data and other critical system resources are protected. If a security policy is written in a natural language specifying for example: ‘file F is only accessible from terminal T in the context C’, it will be very difficult to verify its correct implementation using an automatic testing approach because it is a completely informal specification. Consequently, if such verification is not performed, there is no guarantee that the security rules of the system are properly implemented".

"To guarantee that the system respects its security policy, we can rely on formal testing based methods. The main ones are (i) the active testing which validates a system implementation by applying a set of security test cases and analyzing its reaction and (ii) the monitoring (or passive testing) that consists in observing, during the execution, whether the system behavior is conform according to its functional and security formal specification".

"To perform this analysis, we rely on a dedicated formal language to describe the security requirements of the system. Then, we check using well adapted algorithms whether these security rules are verified on the collected traces to deduce the appropriate verdict about the system security conformance".

W. Mallouli, J.-M. Orset, A. R. Cavalli, N. Cuppens-Boulahia, and F. Cuppens. A formal approach for testing security rules. In V. Lotz and B. M. Thuraisingham, editors, SACMAT, pages 127–132. ACM, 2007. 

To ensure that a certain level of security is always maintained, the system behavior must be restrained by a security policy. A security policy is a set of rules that regulates the nature and the context of actions that can be performed within a system, according to specific roles. As an exam- ple, such policy can tackle the interactions between a network infrastructure and Internet or manage accounts and rights toward an operating system or a database. Generally, a security policy is written by the mean of a natural lan- guage specification, containing statements such as “this file must be accessible only to authorized users” or “all ports are closed except for 21 (ftp), 22 (ssh) and 80 (www)”.

The main problem is that it is quite difficult to verify whether a system implementation conforms to its policy. However, if one can not ensure this conformance, the global security can not be guaranteed anymore. Most current work only concentrate to define meta-languages in order to ex- press security policies and provide unambiguous rules. Once the security policy is formally specified, it is essential to prove that the target system imple- ments this policy by (1) injecting this policy in the system considered or (2) specifying formally the target system and generating proofs that this system implements the security policy or (3) by considering several strategies of formal tests.

Completeness of policy refinement

Source: N. Damianou, A. Bandara, M. Sloman, and E. Lupu. A Survey of Policy Specification Approaches. Technical re- port, Department of Computing, Imperial College of Science Technology and Medicine, London, 2002.

The objective of policy refinement is to transform high-level policy specifications into more specific policies that would be better suited for use in different execution environments.

Definition: (Policy Refinement) If there exists a set of policies Prs:p1, p2, .. pn, such that the enforcement of a combination of these policies results in a system behaving in an identical manner to a system that is enforcing some base policy Pb, it can be said that Prs is a refinement of Pb. The set of policies Prs:p1, p2, .. pn is referred to as the refined policy set.

A policy refinement can be said to complete iff all the following properties hold:
1.    Correctness: a refinement is said to be correct if there exists a subset of the refined policy set such that the conjunction of all the members of that subset is also a refinement of the base policy.
2.    Consistency: refinement is said to be consistent if there are no conflicts between any of the policies in the refined policy set.
3.    Minimality: a refinement is said to be minimal if it is correct and if removing any policy from the refined policy set causes the refinement to be incorrect.

Handling Conflicts between policies

Source: N. Damianou, A. Bandara, M. Sloman, and E. Lupu. A Survey of Policy Specification Approaches. Technical re- port, Department of Computing, Imperial College of Sci-
ence Technology and Medicine, London, 2002.


Jajodia et al. 1997, proposes that a conflict, once detected could be handled in one of three ways. The most obvious and simplest one is for the system to declare an error condition whenever a conflict arises. However, this solution is not particularly interesting since it does not allow for the system to automatically recover from the conflicting scenario. Other solutions are to allow the positive policy to override; or to let the negative policy override. The latter strategy is adopting an approach of ‘‘do no harm’’, based on the assumption that the negative policy (i.e. the one that prevents an action being performed) has a more benign effect on the system than its conflicting counterpart. As would be expected, the positive policy override strategy is the exact converse of the negative override approach described.

In addition to the negative and positive override strategies mentioned above, [Lupu and Sloman 1999] also identifies some alternatives. One approach suggested is to assign explicit priorities to every policy. This way when a conflict arises the agent enforcing the policy could simply compare the priority values and enforce the policy that has the highest priority. However, this approach could easily lead to inconsistent behaviour of the system if, as is common in distributed systems, multiple people are responsible for defining policies and assigning their priorities. Other strategies suggested include giving priority to the policy that is ‘closest’ to the managed object; or using the specificity of the policy definition to determine the priority.

[Moffet and Sloman 1993] introduces the idea of policy hierarchies and the application of policy refinement to derive lower-level, more specific policies from high-level ones.
policy refinement is to transform high-level policy specifications into more specific policies that would be better suited for use in different execution environments.