| ID | Technique | Tactic |
|---|---|---|
| T1562.008 | Disable or Modify Cloud Logs | Defense Evasion |
| T1562 | Impair Defenses | Defense Evasion |
Detection: ASL AWS Defense Evasion Delete Cloudtrail
Description
The following analytic detects AWS DeleteTrail events within CloudTrail logs. It leverages Amazon Security Lake logs parsed in the Open Cybersecurity Schema Framework (OCSF) format to identify when a CloudTrail is deleted. This activity is significant because adversaries may delete CloudTrail logs to evade detection and operate with stealth. If confirmed malicious, this action could allow attackers to cover their tracks, making it difficult to trace their activities and investigate other potential compromises within the AWS environment.
Search
1`amazon_security_lake` api.operation=DeleteTrail
2| fillnull
3| stats count min(_time) as firstTime max(_time) as lastTime by api.operation actor.user.account_uid actor.user.uid http_request.user_agent src_endpoint.ip cloud.region
4| rename actor.user.uid as user, src_endpoint.ip as src_ip, cloud.region as region, http_request.user_agent as user_agent, actor.user.account_uid as aws_account_id
5| `security_content_ctime(firstTime)`
6| `security_content_ctime(lastTime)`
7| `asl_aws_defense_evasion_delete_cloudtrail_filter`
Data Source
No data sources specified for this detection.
Macros Used
| Name | Value |
|---|---|
| amazon_security_lake | sourcetype=aws:cloudtrail:lake |
| asl_aws_defense_evasion_delete_cloudtrail_filter | search * |
asl_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
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
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
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 $user$ has deleted a CloudTrail logging for account id $aws_account_id$ | 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_asl |
aws:cloudtrail:lake |
| Integration | ✅ Passing | Dataset | aws_asl |
aws:cloudtrail:lake |
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: 5