SetDefaultPolicyVersion
AWS
SetDefaultPolicyVersion
Event
Sets the default version of an IAM managed policy, changing which version of the policy is active for all attached entities.
Security Context
- Switching the default policy version activates a pre-staged set of permissions, allowing an attacker to escalate privileges by reverting to or activating a version with broader access.
- This is a known IAM privilege escalation technique — an adversary creates a permissive policy version and then sets it as default to immediately gain elevated access across all attached principals.
Log Source
CloudTrail
Sample Event
Adversarial. Draco rolls a customer-managed policy back to a previously-permissive version: arn:aws:iam::555123456789:policy/OccamyPipelinePolicy version v1 (which, before being patched in v2, granted s3:* on *). Because the policy is attached to multiple service roles, switching the default version v3 → v1 instantly re-grants permissive access across every attached principal — without any AttachPolicy / PutPolicy event firing. T1098.
{ "eventVersion": "1.09", "userIdentity": { "type": "IAMUser", "principalId": "AIDADRAC0MALF0YBADGY", "arn": "arn:aws:iam::555123456789:user/draco", "accountId": "555123456789", "accessKeyId": "AKIADRAC0MALF0YEXAMP5", "userName": "draco", "sessionContext": { "attributes": { "creationDate": "2026-04-15T18:51:02Z", "mfaAuthenticated": "false" } } }, "eventTime": "2026-04-15T20:31:09Z", "eventSource": "iam.amazonaws.com", "eventName": "SetDefaultPolicyVersion", "awsRegion": "us-east-1", "sourceIPAddress": "203.0.113.66", "userAgent": "aws-cli/1.18.147 Python/3.7.10 Linux/5.4.0-1045-aws botocore/1.18.6", "requestParameters": { "policyArn": "arn:aws:iam::555123456789:policy/OccamyPipelinePolicy", "versionId": "v1" }, "responseElements": null, "requestID": "90000000-0000-4000-8000-000110101100", "eventID": "90000000-0000-4000-8000-000110101101", "readOnly": false, "eventType": "AwsApiCall", "managementEvent": true, "recipientAccountId": "555123456789", "eventCategory": "Management", "tlsDetails": { "tlsVersion": "TLSv1.3", "cipherSuite": "TLS_AES_128_GCM_SHA256", "clientProvidedHostHeader": "iam.amazonaws.com" }}MITRE ATT&CK Mapping
Tactics: Privilege Escalation
Techniques:
- T1098 — Account Manipulation — Adversaries may manipulate accounts to maintain and/or elevate access to victim systems. Account manipulation may consist of any action that preserves or modifies adversary access to a compromised account, such as modifying credentials or permission groups. These actions could also include accoun...