Detection: AWS Bedrock Delete GuardRails

Updated Date: 2024-12-05 ID: 7a5e3d62-f743-11ee-9f6e-acde48001122 Author: Bhavin Patel, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies attempts to delete AWS Bedrock GuardRails, which are security controls designed to prevent harmful, biased, or inappropriate AI outputs. It leverages AWS CloudTrail logs to detect when a user or service calls the DeleteGuardrail API. This activity is significant as it may indicate an adversary attempting to remove safety guardrails after compromising credentials, potentially to enable harmful or malicious model outputs. Removing guardrails could allow attackers to extract sensitive information, generate offensive content, or bypass security controls designed to prevent prompt injection and other AI-specific attacks. If confirmed malicious, this could represent a deliberate attempt to manipulate model behavior for harmful purposes.

1`cloudtrail` eventSource=bedrock.amazonaws.com eventName=DeleteGuardrail  
2| rename user_name as user  
3| stats count min(_time) as firstTime max(_time) as lastTime values(requestParameters.guardrailIdentifier) as guardrailIds by src user user_agent vendor_account vendor_product dest signature vendor_region   
4| `security_content_ctime(firstTime)`  
5| `security_content_ctime(lastTime)` 
6| `aws_bedrock_delete_guardrails_filter`

Data Source

Name Platform Sourcetype Source
AWS CloudTrail DeleteGuardrail AWS icon AWS 'aws:cloudtrail' 'aws_cloudtrail'

Macros Used

Name Value
cloudtrail sourcetype=aws:cloudtrail
aws_bedrock_delete_guardrails_filter search *
aws_bedrock_delete_guardrails_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1562.008 Disable or Modify Cloud Logs Defense Evasion
Exploitation
DE.CM
CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

The Splunk AWS Add-on is required to utilize this data. The search requires AWS CloudTrail logs with Bedrock service events enabled. You must install and configure the AWS App for Splunk (version 6.0.0 or later) and Splunk Add-on for AWS (version 5.1.0 or later) to collect CloudTrail logs from AWS. Ensure the CloudTrail is capturing Bedrock GuardRails management events.

Known False Positives

Legitimate administrators may delete GuardRails as part of normal operations, such as when replacing outdated guardrails with updated versions, cleaning up test resources, or consolidating security controls. Consider implementing an allowlist for expected administrators who regularly manage GuardRails configurations.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

User $user$ deleted AWS Bedrock GuardRails $guardrailIds$ from $src$

Risk Object Risk Object Type Risk Score Threat Objects
user user 72 src

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset aws_cloudtrail aws:cloudtrail
Integration ✅ Passing Dataset aws_cloudtrail aws:cloudtrail

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 1