Performing an External Network Security Assessment

B.

As an IS auditor, the first activity to perform during an external network security assessment is reconnaissance.

Reconnaissance is the process of gathering information about a target system or network without actively engaging with it. It is also known as information gathering or footprinting. Reconnaissance helps to identify potential vulnerabilities, weaknesses, and attack vectors that can be used to exploit the network.

Performing reconnaissance as the first step allows the IS auditor to understand the target system and identify potential areas of focus for further testing. The results of reconnaissance activities can help the auditor to determine which vulnerabilities to target, what methods to use, and how to approach the assessment.

The other activities mentioned in the options, such as exploitation, enumeration, and vulnerability scanning, come after reconnaissance. Exploitation involves actively attempting to exploit identified vulnerabilities, which should only be done after proper authorization and careful consideration of the potential impact on the target system. Enumeration involves actively gathering information about the network, such as user accounts, network shares, and system configurations. Vulnerability scanning involves using automated tools to identify potential vulnerabilities in the target system.

In summary, the correct answer is D - Reconnaissance, as it is the first step in an external network security assessment and helps to identify potential vulnerabilities, weaknesses, and attack vectors that can be used to exploit the network.