JetBrains TeamCity Limited Auth Bypass Suricata CVE-2024-27199

name: JetBrains TeamCity Limited Auth Bypass Suricata CVE-2024-27199
id: a1e68dcd-2e24-4434-bd0e-b3d4de139d58
version: 7
date: '2026-03-10'
author: Michael Haag, Splunk
data_source:
    - Suricata
type: TTP
status: production
description: The following analytic identifies attempts to exploit CVE-2024-27199, a critical vulnerability in JetBrains TeamCity web server, allowing unauthenticated access to specific endpoints. It detects unusual access patterns to vulnerable paths such as /res/, /update/, and /.well-known/acme-challenge/ by monitoring HTTP traffic logs via Suricata. This activity is significant as it could indicate an attacker bypassing authentication to access or modify system settings. If confirmed malicious, this could lead to unauthorized changes, disclosure of sensitive information, or uploading of malicious certificates, severely compromising the server's security.
search: |-
    `suricata` http.url IN ("*../admin/diagnostic.jsp*", "*../app/https/settings/*", "*../app/pipeline*", "*../app/oauth/space/createBuild.html*", "*../res/*", "*../update/*", "*../.well-known/acme-challenge/*", "*../app/availableRunners*", "*../app/https/settings/setPort*", "*../app/https/settings/certificateInfo*", "*../app/https/settings/defaultHttpsPort*", "*../app/https/settings/fetchFromAcme*", "*../app/https/settings/removeCertificate*", "*../app/https/settings/uploadCertificate*", "*../app/https/settings/termsOfService*", "*../app/https/settings/triggerAcmeChallenge*", "*../app/https/settings/cancelAcmeChallenge*", "*../app/https/settings/getAcmeOrder*", "*../app/https/settings/setRedirectStrategy*") http.status=200 http_method=GET
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY src, dest, http_user_agent,
           http.url, http.status, http_method
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `jetbrains_teamcity_limited_auth_bypass_suricata_cve_2024_27199_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, however, monitor, filter, and tune as needed based on organization log sources. The analytic is restricted to 200 and GET requests to specific URI paths, which should limit false positives.
references:
    - https://github.com/projectdiscovery/nuclei-templates/blob/f644ec82dfe018890c6aa308967424d26c0f1522/http/cves/2024/CVE-2024-27199.yaml
    - 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 ("$dest$") starthoursago=168  | 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: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: Possible JetBrains TeamCity Limited Authentication Bypass Attempt against $dest$ from $src$.
    risk_objects:
        - field: dest
          type: system
          score: 50
    threat_objects:
        - field: src
          type: ip_address
tags:
    analytic_story:
        - JetBrains TeamCity Vulnerabilities
    asset_type: Web Server
    mitre_attack_id:
        - T1190
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: network
    cve:
        - CVE-2024-27199
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_27199.log
          sourcetype: suricata
          source: not_applicable