Compromise Assessments Expose Missed Intrusions and Security Control Failures

Securelist reported that real-world compromise assessments repeatedly uncovered active and historical intrusions that had bypassed layered defenses, often because basic security controls failed in practice. Investigators linked successful breaches to delayed patching of internet-facing systems, employee and third-party policy violations, missed detections by MSSPs and SOCs, incomplete incident response, and misconfigured or ineffective tooling that left attackers operating undisturbed.

In one case, attackers exploited a late-patched public web server, deployed a SILENTTRINITY C2 stager, used a custom-packed Mimikatz variant and LSASS memory dumping to steal credentials, then performed SMB reconnaissance until gaining domain administrator access. Other assessments found credential exposure through a third-party consultant, repeated webshell activity that an MSSP failed to escalate despite antivirus alerts, and malicious Active Directory Group Policy changes that enabled reversible password storage and weakened Kerberos auditing, underscoring compromise assessment as a last-resort method for finding hidden attacker persistence and validating whether defenses are actually working.