Detection: AWS Defense Evasion Delete Cloudtrail

Updated Date: 2024-09-30 ID: 82092925-9ca1-4e06-98b8-85a2d3889552 Author: Bhavin Patel, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the deletion of AWS CloudTrail logs by identifying DeleteTrail events within CloudTrail logs. This detection leverages CloudTrail data to monitor for successful DeleteTrail actions, excluding those initiated from the AWS console. This activity is significant because adversaries may delete CloudTrail logs to evade detection and operate stealthily within the compromised environment. If confirmed malicious, this action could allow attackers to cover their tracks, making it difficult to trace their activities and potentially leading to prolonged unauthorized access and further exploitation.

1`cloudtrail` eventName = DeleteTrail eventSource = cloudtrail.amazonaws.com userAgent !=console.amazonaws.com errorCode = success
2| stats count min(_time) as firstTime max(_time) as lastTime values(requestParameters.name) as deleted_cloudtrail_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_cloudtrail_filter`

Data Source

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

Macros Used

Name Value
cloudtrail sourcetype=aws:cloudtrail
aws_defense_evasion_delete_cloudtrail_filter search *
aws_defense_evasion_delete_cloudtrail_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
T1562 Impair Defenses Defense Evasion
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
APT29
Magic Hound

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 stopped cloudTrail logging. Please investigate this activity.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
User $user_arn$ has delete a CloudTrail logging 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: 3