Detection: Circle CI Disable Security Job

Updated Date: 2024-05-20 ID: 4a2fdd41-c578-4cd4-9ef7-980e352517f2 Author: Patrick Bareiss, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic detects the disabling of security jobs in CircleCI pipelines. It leverages CircleCI log data, renaming and extracting fields such as job names, workflow IDs, user information, commit messages, URLs, and branches. The detection identifies mandatory jobs for each workflow and checks if they were executed. This activity is significant because disabling security jobs can allow malicious code to bypass security checks, leading to potential data breaches, system downtime, and reputational damage. If confirmed malicious, this could result in unauthorized code execution and compromised pipeline integrity.

Search

 1`circleci` 
 2| rename vcs.committer_name as user vcs.subject as commit_message vcs.url as url workflows.* as *  
 3| stats values(job_name) as job_names by workflow_id workflow_name user commit_message url branch 
 4| lookup mandatory_job_for_workflow workflow_name OUTPUTNEW job_name AS mandatory_job 
 5| search mandatory_job=* 
 6| eval mandatory_job_executed=if(like(job_names, "%".mandatory_job."%"), 1, 0) 
 7| where mandatory_job_executed=0 
 8| eval phase="build" 
 9| rex field=url "(?<repository>[^\/]*\/[^\/]*)$" 
10| `security_content_ctime(firstTime)` 
11| `security_content_ctime(lastTime)` 
12| `circle_ci_disable_security_job_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
CircleCI	N/A	`'circleci'`	`'circleci'`	N/A

Macros Used

Name	Value
circleci	`sourcetype=circleci`
circle_ci_disable_security_job_filter	`search *`

circle_ci_disable_security_job_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
T1554	Compromise Host Software Binary	Persistence

KillChainPhase.INSTALLATION

NistCategory.DE_AE

Cis18Value.CIS_13

APT5

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	True

This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

You must index CircleCI logs.

Known False Positives

unknown

Associated Analytic Story

Dev Sec Ops

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
Disable security job $mandatory_job$ in workflow $workflow_name$ from user $user$	72	80	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.

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`circleci`	`circleci`
Integration	✅ Passing	Dataset	`circleci`	`circleci`

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