Detection: ASL AWS Disable Bucket Versioning

Updated Date: 2024-12-16 ID: f32598bb-fa5f-4afd-8ab3-0263cc28efbc Author: Patrick Bareiss, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic detects when AWS S3 bucket versioning is suspended by a user. It leverages AWS CloudTrail logs to identify PutBucketVersioning events with the VersioningConfiguration.Status set to Suspended. This activity is significant because disabling versioning can prevent recovery of deleted or modified data, which is a common tactic in ransomware attacks. If confirmed malicious, this action could lead to data loss and hinder recovery efforts, severely impacting data integrity and availability.

 1`amazon_security_lake` api.operation=PutBucketVersioning 
 2| spath input=api.request.data path=VersioningConfiguration.Status output=Status 
 3| spath input=api.request.data path=bucketName output=bucketName 
 4| search Status=Suspended 
 5| fillnull 
 6| stats count min(_time) as firstTime max(_time) as lastTime by api.operation actor.user.uid actor.user.account.uid http_request.user_agent src_endpoint.ip cloud.region api.request.data bucketName 
 7| rename actor.user.uid as user, src_endpoint.ip as src_ip, cloud.region as region, http_request.user_agent as user_agent 
 8| `security_content_ctime(firstTime)` 
 9| `security_content_ctime(lastTime)`
10| `asl_aws_disable_bucket_versioning_filter`

Data Source

Name Platform Sourcetype Source
ASL AWS CloudTrail AWS icon AWS 'aws:asl' 'aws_asl'

Macros Used

Name Value
amazon_security_lake sourcetype=aws:asl
asl_aws_disable_bucket_versioning_filter search *
asl_aws_disable_bucket_versioning_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
T1490 Inhibit System Recovery Impact
Actions on Objectives
DE.AE
CIS 10
Sandworm Team
Wizard Spider

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 Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

The detection is based on Amazon Security Lake events from Amazon Web Services (AWS), which is a centralized data lake that provides security-related data from AWS services. To use this detection, you must ingest CloudTrail logs from Amazon Security Lake into Splunk. To run this search, ensure that you ingest events using the latest version of Splunk Add-on for Amazon Web Services (https://splunkbase.splunk.com/app/1876) or the Federated Analytics App.

Known False Positives

It is possible that an AWS Administrator has legitimately disabled versioning on certain buckets to avoid costs.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

Bucket Versioning is suspended for S3 buckets- $bucketName$ by user $user$ from IP address $src_ip$

Risk Object Risk Object Type Risk Score Threat Objects
user user 64 src_ip

References

Detection Testing

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

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