Identifying the incident means verifying whether an incident has occurred and finding out more details about the incident. Once an incident has been confirmed (identified), the incident management team should limit further exposure. Determining the root cause takes place after the incident has been contained. Performing a vulnerability assessment takes place after the root cause of an incident has been determined, in order to find new vulnerabilities.

Explanation
External vulnerability sources are going to be the most cost-effective method of identifying these vulnerabilities. The cost involved in choices B and C would be much higher, especially if performed at regular intervals. Honeypots would not identify all vendor vulnerabilities. In addition, honeypots located in the DMZ can create a security risk if the production network is not well protected from traffic from compromised honey pots.

Without security awareness training, many components of the security program may not be effectively implemented. The other options may or may not be necessary, but are discretionary.