Compromise verification is the process of examining evidence to determine whether an attacker actually accessed or affected a system. A threat actor’s claim or a victim listing can be a warning signal, but neither alone confirms an intrusion.
Defenders verify suspected compromise by correlating authentication and system logs with endpoint telemetry, network activity, and other available records. They may also check for unauthorized changes, unusual outbound traffic, signs of data access, and the integrity of backups. This helps distinguish an attempted attack or unsubstantiated claim from a confirmed breach, and supports a proportionate response based on evidence.