AWS S3 Enumeration
Detection overview
AWS S3 Enumeration is a detection that identifies attempts to list or explore S3 bucket configurations and contents. This activity is often a precursor to malicious actions, such as privilege escalation or data exfiltration. It plays a vital role in identifying early indicators of reconnaissance activities within an AWS environment.
Triggers
- Credential was observed performing a set of anomalous API requests that can be associated with the discovery or subsequent phases of an attack.
Possible Root Causes
- An attacker may be actively looking for privilege escalation opportunities.
- A security or IT service may intentionally be enumerating these APIs for monitoring reasons.
Business Impact
- Privilege escalation may indicate the presence of an adversary that is modifying permissions to progress towards an objective.
Steps to Verify
- Investigate the account context that performed the action for other signs of malicious activity.
- Validate that any modifications are authorized, given the purpose and policies governing this resource.
- If review indicates possible malicious actions or high-risk configuration, revert configuration and disable credentials associated with this alert then perform a comprehensive investigation.
AWS S3 Enumeration
Possible root causes
Malicious Detection
An attacker might enumerate S3 buckets to gather information about their contents, permissions, or configurations as part of reconnaissance. This step is essential in planning further actions like accessing sensitive data or exploiting misconfigured permissions.
Benign Detection
Legitimate administrators or automated processes might perform bucket enumeration during routine checks, migrations, or policy updates. Such activities, though similar in nature, are authorized and aligned with operational needs.
AWS S3 Enumeration
Example scenarios
- Malicious actor probes for access:
An attacker uses stolen credentials to enumerate S3 buckets and locate sensitive configurations or data.
- Administrator troubleshooting:
A legitimate admin lists buckets and objects during a system migration, inadvertently triggering the detection.
AWS S3 Enumeration
Business impact
If this detection indicates a genuine threat, the organization faces significant risks:
Data exposure risk
Unauthorized enumeration could reveal bucket details that expose sensitive information, leading to potential data breaches.
Operational disruption
Reconnaissance activities may indicate imminent attacks that could disrupt business operations.
Compliance challenges
Unmonitored bucket enumerations might lead to violations of regulatory or industry standards.
AWS S3 Enumeration
Steps to investigate
Analyze API usage patterns
Examine the logs to identify the specific API calls that triggered the detection.
Investigate associated credentials
Determine whether the activity was initiated by a known entity or compromised credentials.
Review S3 access policies
Ensure bucket permissions are appropriately restricted to prevent unauthorized access.
Implement temporary mitigations
If unauthorized activity is confirmed, isolate the affected credentials and tighten access controls.