DAILY ANALYSIS
How to verify AWS CloudTrail log integrity
Check signed CloudTrail digests and document which accounts, regions, and time windows the validation covers.
Who is affected
Cloud security and incident response teams rely on CloudTrail records to reconstruct activity. If delivered log files are altered or removed, investigators may draw conclusions from incomplete evidence. CloudTrail can deliver signed digest files that record hashes of delivered logs.
What to do first
Inventory the trails, accounts, and regions that supply your investigation records. Enable log file integrity validation where required and confirm digest delivery to the trail’s S3 bucket. Give the review role read access to the relevant logs and digests and review who can change trail settings or delete evidence.
How to verify the result
In a hypothetical test account, an analyst generates an approved management event, waits for delivery, and uses the AWS CLI CloudTrail validation workflow against the original S3 location. The analyst records the trail, region, UTC interval, and validation outcome. Separately, they confirm the expected event appears in the delivered logs. Repeat for every region and account required by the review.
Follow up on failed checks
Distinguish access errors from missing files and failed integrity checks. Confirm the review role can read the required objects and that digest delivery was enabled during the interval. Preserve relevant logs and digests and escalate unexplained gaps through incident response.
What validation establishes
Validation checks the delivered files covered by the digest chain. The trail’s event selection and delivery coverage require separate checks. Enabling digest delivery starts evidence collection. The team still has to run validation and document its scope.