Detection: ASL AWS Defense Evasion Stop Logging Cloudtrail

Updated Date: 2024-02-12 ID: 0b78a8f9-1d31-4d23-85c8-56ad13d5b4c1 Author: Patrick Bareiss, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects StopLogging events within AWS CloudTrail logs, a critical action that adversaries may use to evade detection. By halting the logging of their malicious activities, attackers aim to operate undetected within a compromised AWS environment. This detection is achieved by monitoring for specific CloudTrail log entries that indicate the cessation of logging activities. Identifying such behavior is crucial for a Security Operations Center (SOC), as it signals an attempt to undermine the integrity of logging mechanisms, potentially allowing malicious activities to proceed without observation. The impact of this evasion tactic is significant, as it can severely hamper incident response and forensic investigations by obscuring the attacker's actions.

1`amazon_security_lake` api.operation=StopLogging 
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_stop_logging_cloudtrail_filter`

Data Source

Name Platform Sourcetype Source Supported App
N/A N/A N/A N/A N/A

Macros Used

Name Value
amazon_security_lake sourcetype=aws:cloudtrail:lake
asl_aws_defense_evasion_stop_logging_cloudtrail_filter search *
asl_aws_defense_evasion_stop_logging_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

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 stopped Cloudtrail logging for account id $aws_account_id$ from IP $src_ip$ 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: 2