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Audit Log (Audit Trail)

What is an Audit Log?

An audit log is a tamper-evident, chronological record of who did what, when, and where in a system — the primary evidence for investigations and compliance.

Last updated: 15 July 2026

What audit logs record

A useful audit log entry answers five questions: who performed the action, what they did, which object it affected, when it happened, and from where. In identity systems that means logins and failures, permission grants and revocations, role changes, policy edits, account creation and deletion, and administrative actions like configuration changes.

Audit logs differ from ordinary application logs in intent. Application logs exist for debugging and can be verbose, transient, and technical. Audit logs exist as evidence: they must be complete for the events they cover, understandable to a reviewer, and protected against modification — including by the administrators whose actions they record.

Why audit logs matter

When an incident happens, the audit trail is often the only way to reconstruct what occurred: which account was used, what was accessed, and whether the attacker changed permissions to persist. Incomplete logging turns a contained incident into an unanswerable question.

Regulatory frameworks lean heavily on audit trails. SOC 2, ISO 27001, GDPR, KVKK, and PCI DSS all expect organizations to log security-relevant events, protect those logs, and retain them for defined periods. Beyond compliance, the existence of a reliable trail deters misuse: people behave differently when actions are attributable.

Audit logging in practice

Centralize logs from identity, access, and privileged systems into storage that is append-only or otherwise tamper-evident, with synchronized clocks so events can be correlated across systems. Define retention to match the strictest applicable requirement, and restrict who can read logs — they often contain sensitive detail.

Logs only deliver value when someone can use them: pair the trail with alerting on high-risk events and with reporting that turns raw entries into reviewable evidence. Identity platforms such as Monosync record provisioning and access review activity and generate audit reports for frameworks like SOC 2, ISO 27001, KVKK, and GDPR.

Frequently asked questions

What is the difference between an audit log and an audit trail?
In practice the terms are used interchangeably. When a distinction is drawn, an audit log is the record produced by a single system, while an audit trail is the reconstructed chain of events across systems that tells the full story of an action from start to finish.
How long should audit logs be retained?
It depends on the applicable regulation and your own incident response needs. Common baselines are one year of readily searchable logs, with several years of archived retention; PCI DSS, for example, requires twelve months with three months immediately available. Legal and compliance teams should set the final policy.
Can administrators modify audit logs?
They should not be able to. A core design requirement is that logs are protected even from privileged users, typically by forwarding entries in real time to a separate, append-only store that administrators of the source system cannot alter. Otherwise an attacker with admin rights can erase their own tracks.