1. Extending a secure development methodology to distributed systems
Yamile Villafuerte
Florida Atlantic University
Advisor: Eduardo B. Fernandez

2. Agenda Methodology Overview
Extending the methodology to distributed applications
Financial Institution Example
Conclusions

3. Methodology Overview
Security principles must be applied at every development stage:
Requirements: List of all possible attacks. Deduce policies to mitigate attacks.
Analysis: Analysis patterns with predefined authorizations based on roles.
Design: Interfaces can be used to enforce authorizations. Distribution provides another dimension where security restrictions can be applied.

4. Extending the Methodology
Choices at the design stage for distributed applications:
Requirements
Analysis
Design
Implementation
Centralized
Distributed
Web Services
Remote Objects
Fixed Network
Wireless
Network

5. Extending the Methodology
How can we keep consistency of the security constraints across all development stages?
How can we represent security constraints in the lower levels?
What are the implications of wireless devices in our design models?
Representation using UML deployment diagrams

6. Wireless Devices Challenges
Limitations:
Limited power
Limited communications bandwidth
Limited processing power
Relatively unreliable network connection
Mobile
Tend to get destroyed accidentally or maliciously
Have effect on security

7. Mapping I Fixed Networks Wireless Networks UML Application
<?xml version=”1.0” ?>
-<Customer = “Info”>
<name>Juan</name>
</Customer>
Web Services
SAML, XML Encryption, XML Signature, XKMS,
WS-Security
CORBA Security, Sec. Broker,
Dist. Objects
UML Application
XML Application
Distribution
Security
Constraints
WS Security
Dist. Objects Security C1 C2
WS1
WS2 O1 O2
XACML
(u1,op1,c1)
SAML
WS-Policy
Simplified
Standards

8. Mapping II
XACML will allow us to express the security constraints defined in the conceptual model in XML
Simplified versions of security standards.

9. Authorization rule using XACML
"Permit manager to open account." There is a lot of XML notation there, but essentially the rule permits a specific subject, to perform a specific action against a specific resource.

10. A Financial Institution Example
Use Case Diagram

11. Analysis Model with RBAC Authorization

12. Design Model

13. Correspondence of Rights
Rights defined for Customer (subject)
Views and wireless devices received a subset of these rights.
Example: Wireless device can not download a complete list of transactions (limited number of records), but can read balance.

14. Correspondence of Rights

15. Conclusions and future work
We presented some ideas of how to map applications and security constraints defined in the analysis stage.
More work needs to be done to elaborate simplified versions of the security standards for web services and to map distribution and hardware.