Detection: AWS Disable Bucket Versioning

Updated Date: 2024-05-24 ID: 657902a9-987d-4879-a1b2-e7a65512824b Author: Bhavin Patel, 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.

Search

1`cloudtrail` eventName= PutBucketVersioning "requestParameters.VersioningConfiguration.Status"=Suspended 
2|  stats count values(requestParameters.bucketName) as bucket_name values(resources{}.ARN) as resource_arn by src_ip aws_account_id awsRegion eventName userAgent user_arn userIdentity.principalId  errorCode 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)`
5| `aws_disable_bucket_versioning_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
AWS CloudTrail PutBucketVersioning	AWS	`'aws:cloudtrail'`	`'aws_cloudtrail'`	N/A

Macros Used

Name	Value
cloudtrail	`sourcetype=aws:cloudtrail`
aws_disable_bucket_versioning_filter	`search *`

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

KillChainPhase.ACTIONS_ON_OBJECTIVES

NistCategory.DE_AE

Cis18Value.CIS_10

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

You must install splunk AWS add on and Splunk App for AWS. This search works with AWS CloudTrail logs.

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	Risk Score	Impact	Confidence
Bucket Versioning is suspended for S3 buckets- $bucket_name$ by user $user_arn$ from IP address $src_ip$	64	80	80

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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: 2