The breach started with silence. No alerts. No traces in the system. The intruder moved through production code as if they had been there for months. Later, we learned why. The audit log—the one meant to record every change—had been altered. History itself had been rewritten. This is the zero day risk that hides inside mutable audit logs.
Audit logs are the spine of trust for any software system. They record who did what, when, and how. But if they can be changed, they are worthless in a serious incident. A skillful attacker who gains write access can remove evidence, create false entries, or bury actions under noise. In a zero day scenario, this destroys the forensic trail before it’s even discovered.
Immutable audit logs solve this. They are write-once records that cannot be altered, even by administrators. Every log entry is cryptographically sealed at the moment of creation. Attempted modifications break signatures and raise alerts. This makes post-incident analysis possible, and it forces attackers to leave a footprint.