JetBrains TeamCity Authentication Bypass Suricata CVE-2024-27198

name: JetBrains TeamCity Authentication Bypass Suricata CVE-2024-27198
id: fbcc04c7-8a79-453c-b3a9-c232c423bdd3
version: 10
creation_date: '2024-03-06'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
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.
data_source:
    - Suricata
search: |-
    `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`
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.
references:
    - 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/
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: Possible JetBrains TeamCity Authentication Bypass Attempt against $dest$ from $src$.
    entity:
        field: dest
        type: system
        score: 50
threat_objects:
    - field: src
      type: ip_address
analytic_story:
    - JetBrains TeamCity Vulnerabilities
    - Hellcat Ransomware
asset_type: Web Server
cve:
    - CVE-2024-27198
mitre_attack_id:
    - T1190
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: web
security_domain: network
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1190/jetbrains/teamcity_cve_2024_27198.log
          sourcetype: suricata
          source: not_applicable
      test_type: unit