AWS Bedrock Unauthorized Resource-Based Policy Modification Attempt

Last updated 3 days ago on 2026-06-04

Created 3 days ago on 2026-06-04

About

Detects failed, access-denied attempts to modify or delete resource-based access policies on AWS Bedrock resources via the PutResourcePolicy and DeleteResourcePolicy API calls. Resource-based policies govern which principals (including external accounts) may access Bedrock resources such as agents, knowledge bases, and custom models. A principal that is repeatedly denied when attempting to attach or remove these policies may be a compromised or under-privileged identity probing for the ability to grant external or cross-account access, or to weaken existing access controls. Unlike the companion rule that detects successful changes, this rule surfaces the attempt itself, which is a high-signal indicator of credential boundary-testing even though no change occurred.

Tags

Domain: CloudDomain: LLMData Source: AWSData Source: AWS CloudTrailData Source: Amazon Web ServicesData Source: Amazon BedrockUse Case: Identity and Access AuditTactic: PersistenceLanguage: kuery

Severity

low

Risk Score

MITRE ATT&CK™

Persistence (TA0003)(external, opens in a new tab or window)

↳ Account Manipulation (T1098)(external, opens in a new tab or window)

False Positive Examples

Access-denied errors can result from benign permission gaps: a newly created role or user whose IAM policy has not yet been provisioned, infrastructure-as-code pipelines running ahead of permission grants, or developers experimenting in non-production accounts. Verify whether the user identity, user agent, and source IP are expected to manage Bedrock resource policies in your environment. Recurring denials from known automation or onboarding workflows can be exempted from the rule.

License

Elastic License v2(external, opens in a new tab or window)

Definition

Rule Type: Query (Kibana Query Language)
Integration Pack: Prebuilt Security Detection Rules
Index Patterns: logs-aws.cloudtrail-*
Related Integrations: aws(external, opens in a new tab or window)
Query

✄𐘗text code block:
✄𐘗data_stream.dataset: "aws.cloudtrail" and
    event.provider: "bedrock.amazonaws.com" and
    event.action: ("PutResourcePolicy" or "DeleteResourcePolicy") and
    event.outcome: "failure" and
    aws.cloudtrail.error_code: (
        "AccessDenied" or
        "AccessDeniedException"
    )

Install detection rules in Elastic Security

Detect AWS Bedrock Unauthorized Resource-Based Policy Modification Attempt in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(external, opens in a new tab or window).