AWS Exfiltration via Anomalous GetObject API Activity
The following analytic identifies anomalous GetObject API activity in AWS, indicating potential data exfiltration attempts. It leverages AWS CloudTrail logs and uses the `anomalydetection` command to detect unusual…
Description
The following analytic identifies anomalous GetObject API activity in AWS, indicating potential data exfiltration attempts. It leverages AWS CloudTrail logs and uses the `anomalydetection` command to detect unusual patterns in the frequency of GetObject API calls by analyzing fields such as "count," "user_type," and "user_arn" within a 10-minute window. This activity is significant as it may indicate unauthorized data access or exfiltration from S3 buckets. If confirmed malicious, attackers could exfiltrate sensitive data, leading to data breaches and compliance violations.
Detection logic
Detection requirements
- Platform
- IaaSLinuxmacOSOffice SuiteSaaSWindows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
- Log source category
- aws_cloudtrail_getobject
Known benign triggers
- It is possible that a user downloaded these files to use them locally and there are AWS services in configured that perform these activities for a legitimate reason. Filter is needed.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| help.splunk.com/en/splunk-enterprise/search/spl-search-reference/9.4/search-commands/anomalydetection | Only this detection cites it |
| labs.nettitude.com/blog/how-to-exfiltrate-aws-ec2-data/ | 7 |
| www.vectra.ai/blogpost/abusing-the-replicator-silently-exfiltrating-data-with-the-aws-s3-replication-service | Only this detection cites it |
From the source
- At source
- Open at source
- Upstream identifier
- e4384bbf-5835-4831-8d85-694de6ad2cc6
- Tagged by the source as
- Data ExfiltrationAWS AccountcloudSplunk CloudSplunk EnterpriseSplunk Enterprise Securitythreat
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Aug 26, 2026
- Version
- 1