Section: INFORMATION SECURITY PROGRAM MANAGEMENT

Explanation/Reference:
Explanation:
Screened subnets are demilitarized zones (DMZs) and are oriented toward preventing attacks on an internal network by external users. The policies and procedures to classify information will ultimately result in better protection but they will not prevent actual modification. Role-based access controls would help ensure that users only had access to files and systems appropriate for their job role. Intrusion detection systems (IDS) are useful to detect invalid attempts but they will not prevent attempts.

Explanation
Only reviewing transaction and application logs directly addresses the threat posed by poor segregation of duties. The review is a means of detecting inappropriate behavior and also discourages abuse, because people who may otherwise be tempted to exploit the situation are aware of the likelihood of being caught. Inadequate segregation of duties is more likely to be exploited via logical access to data and computing resources rather than physical access. Choice C is a useful control to ensure IT staff are trustworthy and competent but does not directly address the lack of an optimal segregation of duties. Choice D acts to prevent unauthorized users from gaining system access, but the issue of a lack of segregation of duties is more the misuse (deliberately or inadvertently} of access privileges that have officially been granted.

Section: INFORMATION SECURITY PROGRAM MANAGEMENT