postcompromise

Postcompromise refers to the period after a cybersecurity breach when an attacker has gained access to a system and may have established footholds, persisted through credentials or backdoors, and attempted to expand access or exfiltrate data. In incident response, postcompromise focuses on identifying the attacker’s presence, understanding the scope of the compromise, eradicating malicious access, and restoring normal operations while preventing further damage.

Common characteristics of postcompromise activity include persistence mechanisms such as backdoors, scheduled tasks, rogue or stolen credentials, compromised administrator or service accounts, and undetected channeling of data through covert communications. Attackers may move laterally, harvest credentials, manipulate logs to obscure activity, and maintain covert channels for ongoing access. Detecting postcompromise activity is challenging due to stealth techniques, overlapping legitimate activity, and the attacker’s attempts to blend in with normal operations.

The postcompromise lifecycle typically comprises detection and scope assessment, containment and eradication of attacker access, recovery and system restoration, and post-incident analysis with hardening of defenses. Threat hunting, comprehensive log review, endpoint detection and response, network telemetry, and verification of backups are common practices during this phase. Organizations aim to remove all footholds, reset compromised credentials, patch vulnerabilities, and restore trust.

Key mitigation strategies include implementing least-privilege access, multi-factor authentication, network segmentation, continuous monitoring, and a robust incident response plan. Regular backups, tested disaster recovery, and the application of zero-trust principles help reduce risk during postcompromise. The concept emphasizes preparedness and resilience as much as it does remediation.

See also: incident response, threat hunting, MITRE ATT&CK, zero trust, endpoint detection and response.