Sommerville-Software-Engineering-10ed

406 Chapter 13 ■ Security engineering
Exercises
13.1. Describe the security dimensions and security levels that have to be considered in secure
systems engineering.
13.2. For the Mentcare system, suggest an example of an asset, an exposure, a vulnerability, an
attack, a threat, and a control, in addition to those discussed in this chapter.
13.3. Explain why security is considered a more challenging problem than safety in a system.
13.4. Extend the table in Figure 13.7 to identify two further threats to the Mentcare system, along
with associated controls. Use these as a basis for generating software security requirements
that implement the proposed controls.
13.5. Explain, using an analogy drawn from a non-software engineering context, why a layered
approach to asset protection should be used.
13.6. Explain why it is important to log user actions in the development of secure systems.
13.7. For the equity trading system discussed in Section 13.4.2, whose architecture is shown in
Figure 13.14, suggest two further plausible attacks on the system and propose possible strategies
that could counter these attacks.
13.8. Explain why it is important when writing secure systems to validate all user inputs to check
that these have the expected format.
13.9. Suggest how you would go about validating a password protection system for an application
that you have developed. Explain the function of any tools that you think may be useful.
13.10. The Mentcare system has to be secure against attacks that might reveal confidential patient
information. Suggest three possible attacks against this system that might occur. Using this
information, extend the checklist in Figure 13.17 to guide testers of the Mentcare system.
References
Anderson, R. 2008. Security Engineering, 2nd ed. Chichester, UK: John Wiley & Sons.
Cranor, L. and S. Garfinkel. 2005. Designing Secure Systems That People Can Use. Sebastopol, CA:
O’Reilly Media Inc.
Firesmith, D. G. 2003. “Engineering Security Requirements.” Journal of Object Technology 2 (1):
53–68. http://www.jot.fm/issues/issue_2003_01/column6
Hall, A., and R. Chapman. 2002. “Correctness by Construction: Developing a Commercially Secure
System.” IEEE Software 19 (1): 18–25. doi:10.1109/52.976937.
Hewlett-Packard. 2012. “Securing Your Enterprise Software: Hp Fortify Code Analyzer.” http://
h20195.www2.hp.com/V2/GetDocument.aspx?docname=4AA4-2455ENW&cc=us&lc=en