ID | Technique | Tactic |
---|---|---|
T1562.008 | Disable or Modify Cloud Logs | Defense Evasion |
T1562 | Impair Defenses | Defense Evasion |
T1485.001 | Lifecycle-Triggered Deletion | Impact |
T1485 | Data Destruction | Impact |
Detection: AWS Defense Evasion PutBucketLifecycle
Description
The following analytic detects PutBucketLifecycle
events in AWS CloudTrail logs where a user sets a lifecycle rule for an S3 bucket with an expiration period of fewer than three days. This detection leverages CloudTrail logs to identify suspicious lifecycle configurations. This activity is significant because attackers may use it to delete CloudTrail logs quickly, thereby evading detection and impairing forensic investigations. If confirmed malicious, this could allow attackers to cover their tracks, making it difficult to trace their actions and respond to the breach effectively.
Search
1`cloudtrail` eventName=PutBucketLifecycle user_type=IAMUser errorCode=success
2| spath path=requestParameters{}.LifecycleConfiguration{}.Rule{}.Expiration{}.Days output=expiration_days
3| spath path=requestParameters{}.bucketName output=bucket_name
4| stats count min(_time) as firstTime max(_time) as lastTime by src region eventName userAgent user_arn aws_account_id expiration_days bucket_name user_type
5| `security_content_ctime(firstTime)`
6| `security_content_ctime(lastTime)`
7| where expiration_days < 3
8| `aws_defense_evasion_putbucketlifecycle_filter`
Data Source
Name | Platform | Sourcetype | Source |
---|---|---|---|
AWS CloudTrail PutBucketLifecycle | AWS | 'aws:cloudtrail' |
'aws_cloudtrail' |
Macros Used
Name | Value |
---|---|
cloudtrail | sourcetype=aws:cloudtrail |
aws_defense_evasion_putbucketlifecycle_filter | search * |
aws_defense_evasion_putbucketlifecycle_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 | False |
Implementation
You must install Splunk AWS Add on and enable CloudTrail logs in your AWS Environment. We recommend our users to set the expiration days value according to your company's log retention policies.
Known False Positives
While this search has no known false positives, it is possible that it is a legitimate admin activity. Please consider filtering out these noisy events using userAgent, user_arn field names.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
User $user_arn$ has created a new rule to on an S3 bucket $bucket_name$ with short expiration days | 20 | 50 | 40 |
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: 3