Detection: AWS Defense Evasion Delete CloudWatch Log Group

Updated Date: 2024-05-26 ID: d308b0f1-edb7-4a62-a614-af321160710f Author: Gowthamaraj Rajendran, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the deletion of CloudWatch log groups in AWS, identified through DeleteLogGroup events in CloudTrail logs. This detection leverages CloudTrail data to monitor for successful log group deletions, excluding console-based actions. This activity is significant as it indicates potential attempts to evade logging and monitoring, which is crucial for maintaining visibility into AWS activities. If confirmed malicious, this could allow attackers to hide their tracks, making it difficult to detect further malicious actions or investigate incidents within the compromised AWS environment.

1`cloudtrail` eventName = DeleteLogGroup eventSource = logs.amazonaws.com userAgent !=console.amazonaws.com errorCode = success
2| stats count min(_time) as firstTime max(_time) as lastTime values(requestParameters.logGroupName) as log_group_name by src region eventName userAgent user_arn aws_account_id 
3| `security_content_ctime(firstTime)`
4| `security_content_ctime(lastTime)`
5| `aws_defense_evasion_delete_cloudwatch_log_group_filter`

Data Source

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

Macros Used

Name Value
cloudtrail sourcetype=aws:cloudtrail
aws_defense_evasion_delete_cloudwatch_log_group_filter search *
aws_defense_evasion_delete_cloudwatch_log_group_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 Impair Defenses Defense Evasion
T1562.008 Disable or Modify Cloud Logs Defense Evasion
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
Magic Hound
APT29

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

You must install Splunk AWS Add on and enable CloudTrail logs in your AWS Environment.

Known False Positives

While this search has no known false positives, it is possible that an AWS admin has deleted CloudWatch logging. Please investigate this activity.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
User $user_arn$ has deleted a CloudWatch logging group for account id $aws_account_id$ from IP $src$ 90 100 90
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