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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.

  • Type: TTP

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

  • Last Updated: 2024-05-26
  • Author: Michael Haag, Splunk
  • ID: a1e68dcd-2e24-4434-bd0e-b3d4de139d58

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
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`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`

Macros

The SPL above uses the following Macros:

:information_source: jetbrains_teamcity_limited_auth_bypass_suricata_cve-2024-27199_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_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, 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.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
63.0 90 70 Possible JetBrains TeamCity Limited 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