Detection: AWS Bedrock Delete Model Invocation Logging Configuration

Updated Date: 2024-12-05 ID: 9c5e3d62-f743-11ee-9f6e-acde48001124 Author: Bhavin Patel, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies attempts to delete AWS Bedrock model invocation logging configurations. It leverages AWS CloudTrail logs to detect when a user or service calls the DeleteModelInvocationLogging API. This activity is significant as it may indicate an adversary attempting to remove audit trails of model interactions after compromising credentials. Deleting model invocation logs could allow attackers to interact with AI models without leaving traces, potentially enabling them to conduct data exfiltration, prompt injection attacks, or other malicious activities without detection. If confirmed malicious, this could represent a deliberate attempt to hide unauthorized model usage and evade detection.

1`cloudtrail` eventSource=bedrock.amazonaws.com eventName=DeleteModelInvocationLoggingConfiguration  
2| rename user_name as user  
3| stats count min(_time) as firstTime max(_time) as lastTime 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_model_invocation_logging_configuration_filter`

Data Source

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

Macros Used

Name Value
cloudtrail sourcetype=aws:cloudtrail
aws_bedrock_delete_model_invocation_logging_configuration_filter search *
aws_bedrock_delete_model_invocation_logging_configuration_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 model invocation logging management events.

Known False Positives

Legitimate administrators may delete model invocation logging configurations during maintenance, when updating logging policies, or when cleaning up unused resources. Consider implementing an allowlist for expected administrators who regularly manage logging configurations.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

User $user$ deleted AWS Bedrock model invocation logging from $src$

Risk Object Risk Object Type Risk Score Threat Objects
user user 75 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