An intrusion detection system logged an attack attempt from a remote IP address. One week later, the attacker successfully compromised the network. Which of the following MOST likely occurred?

False negatives occur when an IDS fails to detect a real attack; this scenario explicitly states the IDS did log the attack attempt, which means false negatives were not the cause of the eventual compromise.

The time of the attack is irrelevant if logs are reviewed regularly - there is no indication in the scenario that after-hours monitoring gaps existed or contributed to the outcome.

False positives are benign events incorrectly flagged as malicious; the IDS accurately identified a real attack attempt, so alert fatigue from false positives is not supported by the scenario.

An IDS is only effective if its alerts are actively monitored and investigated - the attack attempt was logged, confirming detection worked correctly, but the absence of any response indicates that no one reviewed the event logs, leaving the vulnerability unaddressed and giving the attacker time to plan and execute a successful follow-up intrusion.