JetBrains TeamCity Authentication Bypass CVE-2024-27198

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Description

The following analytic identifies attempts to exploit the JetBrains TeamCity Authentication Bypass vulnerability (CVE-2024-27198). It detects suspicious POST requests to the /app/rest/users and /app/rest/users/id:1/tokens endpoints, which are indicative of attempts to create new administrator users or generate admin access tokens without authentication. This detection leverages the Web datamodel and CIM-compliant log sources, such as Nginx or TeamCity logs. This activity is significant as it can lead to full control over the TeamCity server, including all projects, builds, agents, and artifacts. If confirmed malicious, attackers could gain unauthorized administrative access, leading to severe security breaches.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Web
• Last Updated: 2024-05-20
• Author: Michael Haag, Splunk
• ID: fbcc04c7-8a79-453c-b3a9-c232c423bdd4

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1190	Exploit Public-Facing Application	Initial Access

Kill Chain Phase

• Delivery

NIST

• DE.CM

CIS20

• CIS 13

CVE

Search

| tstats count min(_time) as firstTime max(_time) as lastTime from datamodel=Web where ((Web.url="*?jsp=*" AND Web.url="*;.jsp*") Web.status=200 Web.http_method=POST) OR (Web.url IN ("*jsp=/app/rest/users;.jsp","*?jsp=/app/rest/users;.jsp","*?jsp=.*/app/rest/users/id:*/tokens;*") Web.status=200 Web.http_method=POST ) by Web.src, Web.dest, Web.http_user_agent, Web.url, Web.status, Web.http_method, sourcetype, source 
| `drop_dm_object_name("Web")` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)`
| `jetbrains_teamcity_authentication_bypass_cve_2024_27198_filter`

Macros

The SPL above uses the following Macros:

• security_content_ctime

jetbrains_teamcity_authentication_bypass_cve-2024-27198_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

• Web.src
• Web.dest
• Web.http_user_agent
• Web.url
• Web.status
• Web.http_method
• sourcetype
• source

How To Implement

The detection relies on the Web datamodel and a CIM compliant log source, that may include Nginx, TeamCity logs, or other web server logs.

Known False Positives

False positives are not expected, as this detection is based on the presence of specific URI paths and HTTP methods that are indicative of the CVE-2024-27198 vulnerability exploitation. Monitor, filter and tune as needed based on organization log sources.

Associated Analytic Story

• JetBrains TeamCity Vulnerabilities

RBA

Risk Score	Impact	Confidence	Message
81.0	90	90	Possible JetBrains TeamCity Authentication Bypass CVE-2024-27198 Attempt against $dest$ from $src$.

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• https://github.com/projectdiscovery/nuclei-templates/pull/9279/files
• https://www.rapid7.com/blog/post/2024/03/04/etr-cve-2024-27198-and-cve-2024-27199-jetbrains-teamcity-multiple-authentication-bypass-vulnerabilities-fixed/
• https://blog.jetbrains.com/teamcity/2024/03/teamcity-2023-11-4-is-out/
• https://blog.jetbrains.com/teamcity/2024/03/additional-critical-security-issues-affecting-teamcity-on-premises-cve-2024-27198-and-cve-2024-27199-update-to-2023-11-4-now/
• https://github.com/yoryio/CVE-2024-27198/blob/main/CVE-2024-27198.py

Test Dataset

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 | version: 2