AWS CloudTrail: Suspicious STS AssumeRole sessions from Role-issued principals

Alert on CloudTrail AssumeRole events initiated from an already assumed role session.

FreeReviewedSigma · Low · v5

Product: aws
Service: cloudtrail
Author: Austin Songer @austinsonger (SigmaHQ), DRL 1.1
Published: 2021-07-24
Updated: 2026-07-31

ATT&CK techniques

Priv Esc → Lateral Movement

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
- T1548Abuse Elevation Control Mechanism
Defense Evasion
Cred Access
Discovery
Lateral Movement
- T1550Use Alternate Authentication Material
- T1550.001Application Access Token
Collection
C2
Exfiltration
Impact

What it detects

This rule flags CloudTrail events where the caller’s identity is an assumed role session and the session issuer is of type Role. Such activity can indicate attackers using AWS STS AssumeRole to obtain new credentials, enabling lateral movement and privilege changes within the AWS environment. The detection relies on CloudTrail userIdentity and sessionContext fields that describe the assumed role and its role issuer.

Reporting behind it

Related detections9 linkedT1550.001 — drag to rearrange

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Suspicious AWS Role Assumption via Cognito Web Identity

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AWS CloudTrail: Suspicious STS AssumeRole sessions from Role-issued principals

Pivot detection · T1550.001 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

aws-cloudtrail-detect-assumerole-events-where-the-caller-is-an-assumed-role-905d389b

title: "AWS CloudTrail: Suspicious STS AssumeRole sessions from Role-issued principals"
id: 3f41df0b-64e7-4c8f-8201-d492469e372b
status: test
description: This rule flags CloudTrail events where the caller’s identity is an assumed role session and the session issuer is of type Role. Such activity can indicate attackers using AWS STS AssumeRole to obtain new credentials, enabling lateral movement and privilege changes within the AWS environment. The detection relies on CloudTrail userIdentity and sessionContext fields that describe the assumed role and its role issuer.
references:
  - https://github.com/elastic/detection-rules/pull/1214
  - https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html
  - https://github.com/SigmaHQ/sigma/blob/master/rules/cloud/aws/cloudtrail/aws_sts_assumerole_misuse.yml
author: Austin Songer @austinsonger, Huntrule Team
date: 2021-07-24
modified: 2022-10-09
tags:
  - attack.lateral-movement
  - attack.privilege-escalation
  - attack.t1548
  - attack.t1550
  - attack.t1550.001
logsource:
  product: aws
  service: cloudtrail
detection:
  selection:
    userIdentity.type: AssumedRole
    userIdentity.sessionContext.sessionIssuer.type: Role
  condition: selection
falsepositives:
  - AssumeRole may be done by a system or network administrator. Verify whether the user identity, user agent, and/or hostname should be making changes in your environment.
  - AssumeRole from unfamiliar users or hosts should be investigated. If known behavior is causing false positives, it can be exempted from the rule.
  - Automated processes that uses Terraform may lead to false positives.
level: low
license: DRL-1.1
related:
  - id: 905d389b-b853-46d0-9d3d-dea0d3a3cd49
    type: derived

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