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Description

The following analytic detects attempts to exploit the CVE-2024-27198 vulnerability in JetBrains TeamCity on-premises servers, which allows attackers to bypass authentication mechanisms. It leverages Suricata HTTP traffic logs to identify suspicious POST requests to the /app/rest/users and /app/rest/users/id:1/tokens endpoints. This activity is significant because it can lead to unauthorized administrative access, enabling attackers to gain full control over the TeamCity server, including projects, builds, agents, and artifacts. If confirmed malicious, this could result in severe security breaches and compromise the integrity of the development environment.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-16
  • Author: Michael Haag, Splunk
  • ID: fbcc04c7-8a79-453c-b3a9-c232c423bdd3

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 


1
2
3
4
5



`suricata` ((http.url="*?jsp=*" AND http.url="*;.jsp*") http.status=200 http_method=POST) OR (http.url IN ("*jsp=/app/rest/users;.jsp","*?jsp=/app/rest/users;.jsp","*?jsp=.*/app/rest/users/id:*/tokens;*") http.status=200 http_method=POST ) 
| stats count min(_time) as firstTime max(_time) as lastTime by src, dest, http.http_user_agent, http.url, http.status,http_method 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)`
| `jetbrains_teamcity_authentication_bypass_suricata_cve_2024_27198_filter`

Macros

The SPL above uses the following Macros:

:information_source: jetbrains_teamcity_authentication_bypass_suricata_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.

  • src
  • dest
  • http.http_user_agent
  • http.url
  • http.status
  • http_method

How To Implement

The following detection relies on the Suricata TA and ensuring it is properly configured to monitor HTTP traffic. Modify the query for your environment and log sources as needed.

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

RBA

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

:information_source: 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

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