AWS IAM Role's Trusted Policy Modification Allows Cross-Account Access

Synopsis

Field	Value
Activation Period	14 Days
Training Period	30 Days
Test Period	N/A (single event)
Deduplication Period	5 Days
Required Data	AWS Audit Log
Detection Modules	Cloud
ATT&CK Tactic	Persistence (TA0003)
ATT&CK Technique	Account Manipulation: Additional Cloud Roles (T1098.003), Account Manipulation (T1098)
Severity	Low

Description

A cloud identity has updated an IAM role's trust policy to allow external AWS account access.

Attacker's Goals

Obtaining persistency by assuming a role in the target's environment.

Investigative actions

• Investigate any unusual activity originating from the suspected identity.
• Investigate any unusual activity performed in the assumed role sessions when originating from the allowed added accounts.
• Validate the legitimacy of the AWS accounts that were allowed external access.