Nginx ConnectWise ScreenConnect Authentication Bypass

name: Nginx ConnectWise ScreenConnect Authentication Bypass
id: b3f7a803-e802-448b-8eb2-e796b223bccc
version: 11
creation_date: '2024-02-22'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic detects attempts to exploit the ConnectWise ScreenConnect CVE-2024-1709 vulnerability, which allows attackers to bypass authentication via alternate paths or channels. It leverages Nginx access logs to identify web requests to the SetupWizard.aspx page, indicating potential exploitation. This activity is significant as it can lead to unauthorized administrative access and remote code execution. If confirmed malicious, attackers could create administrative users and gain full control over the affected ScreenConnect instance, posing severe security risks. Immediate remediation by updating to version 23.9.8 or above is recommended.
data_source:
    - Nginx Access
search: |-
    `nginx_access_logs` uri_path IN ("*/SetupWizard.aspx/*","*/SetupWizard/") status=200 http_method=POST
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY src, dest, http_user_agent,
           url, uri_path, status,
           http_method, sourcetype, source
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `nginx_connectwise_screenconnect_authentication_bypass_filter`
how_to_implement: To implement this analytic, ensure proper logging is occurring with Nginx, access.log and error.log, and that these logs are being ingested into Splunk. STRT utilizes this nginx.conf https://gist.github.com/MHaggis/26f59108b04da8f1d870c9cc3a3c8eec to properly log as much data with Nginx.
known_false_positives: False positives are not expected, as the detection is based on the presence of web requests to the SetupWizard.aspx page, which is not a common page to be accessed by legitimate users. Note that the analytic is limited to HTTP POST and a status of 200 to reduce false positives. Modify the query as needed to reduce false positives or hunt for additional indicators of compromise.
references:
    - https://docs.splunk.com/Documentation/AddOns/released/NGINX/Sourcetypes
    - https://gist.github.com/MHaggis/26f59108b04da8f1d870c9cc3a3c8eec
    - https://www.huntress.com/blog/a-catastrophe-for-control-understanding-the-screenconnect-authentication-bypass
    - https://www.huntress.com/blog/detection-guidance-for-connectwise-cwe-288-2
    - https://www.connectwise.com/company/trust/security-bulletins/connectwise-screenconnect-23.9.8
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: An authentication bypass attempt against ScreenConnect has been detected on $dest$.
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - ConnectWise ScreenConnect Vulnerabilities
    - Seashell Blizzard
    - Scattered Lapsus$ Hunters
    - Hellcat Ransomware
asset_type: Web Proxy
cve:
    - CVE-2024-1708
    - CVE-2024-1709
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/screenconnect/nginx_screenconnect.log
          sourcetype: nginx:plus:kv
          source: nginx:plus:kv
      test_type: unit