Section: Information System Acquisition, Development and Implementation

Section: Protection of Information Assets
Explanation:
A write-once CD cannot be overwritten. Therefore, the system log duplicated on the disk could be compared to the original log to detect differences, which could be the result of changes made by an intruder. Write-protecting the system log does not prevent deletion or modification, since the superuser can override the write protection. Backup and mirroring may overwrite earlier files and may not be current.

Section: Protection of Information Assets
Explanation:
An IS auditor should focus on when controls are exercised as data flow through a computer system. Choice
B is incorrect since corrective controls may also be relevant. Choice C is incorrect, since corrective controls
remove or reduce the effects of errors or irregularities and are exclusively regarded as compensating
controls. Choice D is incorrect and irrelevant since the existence and function of controls is important, not
the classification.

Explanation/Reference:
Explanation:
When designing controls, it is necessary to consider all the above aspects. In an ideal situation, controls that address all these aspects would be the best controls. Realistically, it may not be possible to design them all and cost may be prohibitive; therefore, it is necessary to first consider the preventive controls that attack the cause of a threat.