JetBrains TeamCity RCE Attempt

Description

The following analytic detects attempts to exploit the CVE-2023-42793 vulnerability in JetBrains TeamCity On-Premises. It identifies suspicious POST requests to /app/rest/users/id:1/tokens/RPC2, leveraging the Web datamodel to monitor specific URL patterns and HTTP methods. This activity is significant as it may indicate an unauthenticated attacker attempting to gain administrative access via Remote Code Execution (RCE). If confirmed malicious, this could allow the attacker to execute arbitrary code, potentially compromising the entire TeamCity environment and leading to further unauthorized access and data breaches.

Query · spl

| tstats `security_content_summariesonly`
  count min(_time) as firstTime
        max(_time) as lastTime

FROM datamodel=Web WHERE

Web.url="*/app/rest/users/id:1/tokens/RPC2*"
Web.status=200
Web.http_method="POST"

BY Web.http_user_agent Web.status Web.http_method
   Web.url Web.url_length Web.src Web.dest

| `drop_dm_object_name("Web")`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `jetbrains_teamcity_rce_attempt_filter`

Implementation guide

The following analytic requires the Web datamodel. Ensure data source is mapped correctly or modify and tune for your data source.

Known false positives

  • Requests to this specific endpoint via this method should not be common. Investigate further to determine if the request is legitimate, and apply appropriate filters to reduce false positives.

Analyst notes

Known false positives: Requests to this specific endpoint via this method should not be common. Investigate further to determine if the request is legitimate, and apply appropriate filters to reduce false positives.

Raw source JetBrains TeamCity RCE Attempt · SPL
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Published by splunk/security_content ↗, licensed under Apache 2.0 ↗. Reproduced here unmodified. 
name: JetBrains TeamCity RCE Attempt
id: 89a58e5f-1365-4793-b45c-770abbb32b6c
version: 11
creation_date: '2023-10-01'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: |-
    The following analytic detects attempts to exploit the CVE-2023-42793 vulnerability in JetBrains TeamCity On-Premises.
    It identifies suspicious POST requests to /app/rest/users/id:1/tokens/RPC2, leveraging the Web datamodel to monitor specific URL patterns and HTTP methods.
    This activity is significant as it may indicate an unauthenticated attacker attempting to gain administrative access via Remote Code Execution (RCE).
    If confirmed malicious, this could allow the attacker to execute arbitrary code, potentially compromising the entire TeamCity environment and leading to further unauthorized access and data breaches.
data_source:
    - Suricata
search: |-
    | tstats `security_content_summariesonly`
      count min(_time) as firstTime
            max(_time) as lastTime

    FROM datamodel=Web WHERE

    Web.url="*/app/rest/users/id:1/tokens/RPC2*"
    Web.status=200
    Web.http_method="POST"

    BY Web.http_user_agent Web.status Web.http_method
       Web.url Web.url_length Web.src Web.dest

    | `drop_dm_object_name("Web")`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `jetbrains_teamcity_rce_attempt_filter`
how_to_implement: |-
    The following analytic requires the Web datamodel. Ensure data source is mapped correctly or modify and tune for your data source.
known_false_positives: |-
    Requests to this specific endpoint via this method should not be common. Investigate further to determine if the request is legitimate, and apply appropriate filters to reduce false positives.
references:
    - https://blog.jetbrains.com/teamcity/2023/09/critical-security-issue-affecting-teamcity-on-premises-update-to-2023-05-4-now/
    - https://www.sonarsource.com/blog/teamcity-vulnerability/
    - https://github.com/rapid7/metasploit-framework/pull/18408
    - https://attackerkb.com/topics/1XEEEkGHzt/cve-2023-42793/rapid7-analysis
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: Potential JetBrains TeamCity RCE Attempt detected against URL $url$ on $dest$.
    entity:
        field: dest
        type: system
        score: 50
threat_objects:
    - field: src
      type: ip_address
analytic_story:
    - JetBrains TeamCity Unauthenticated RCE
    - CISA AA23-347A
    - JetBrains TeamCity Vulnerabilities
asset_type: Web Server
cve:
    - CVE-2023-42793
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.log
          source: not_applicable
          sourcetype: suricata
      test_type: unit

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