Which of the following is a common network vulnerability?

A common network vulnerability is unpatched software or firmware, as this condition creates an opportunity for attackers to exploit known weaknesses. Software and firmware are regularly updated to patch security flaws and vulnerabilities that can be targeted by cybercriminals. When systems are not kept up-to-date, they remain susceptible to threats that can lead to unauthorized access, data breaches, or other malicious activities.

Regular network traffic does not constitute a vulnerability; it represents normal operation within a network. Secure administrative passwords act as a protective measure against unauthorized access, while hardware encryption methods enhance data security. It is the absence of necessary updates, as seen in unpatched software or firmware, that presents a significant risk in the security posture of a network.