connectwise_screenconnect_authentication_bypass.yml

name: ConnectWise ScreenConnect Authentication Bypass
id: d3f7a803-e802-448b-8eb2-e796b223bfff
version: 2
date: '2024-02-23'
author: Michael Haag, Splunk
data_source: 
- Suricata
type: TTP
status: production
description: This analytic detects attempts to exploit the ConnectWise ScreenConnect CVE-2024-1709 vulnerability, which allows an attacker to bypass authentication using an alternate path or channel. The vulnerability, identified as critical with a CVSS score of 10, enables unauthorized users to access the SetupWizard.aspx page on already-configured ScreenConnect instances, potentially leading to the creation of administrative users and remote code execution. The search query provided looks for web requests to the SetupWizard.aspx page that could indicate exploitation attempts. This detection is crucial for identifying and responding to active exploitation of this vulnerability in environments running affected versions of ScreenConnect (23.9.7 and prior). It is recommended to update to version 23.9.8 or above immediately to remediate the issue, as detailed in the ConnectWise security advisory and further analyzed by Huntress researchers.
search: '| tstats count min(_time) as firstTime max(_time) as lastTime from datamodel=Web where Web.url IN ("*/SetupWizard.aspx/*","*/SetupWizard/") Web.status=200 Web.http_method=POST by Web.src, Web.dest, Web.http_user_agent, Web.url, Web.status, Web.http_method, sourcetype, source
  | rex field=Web.url "/SetupWizard.aspx/(?<randomPath>.+)"
  | `drop_dm_object_name("Web")`
  | `security_content_ctime(firstTime)` 
  | `security_content_ctime(lastTime)`
  | `connectwise_screenconnect_authentication_bypass_filter`'
how_to_implement: To implement this analytic, ensure proper logging is occurring with IIS, Apache, or a Proxy server and that these logs are being ingested into Splunk. The analytic was written against Suricata. The proper TA will need to be enabled and should be mapped to CIM and the Web datamodel. Ingestion of the data source is required to utilize this detection. In addition, if it is not mapped to the datamodel, modify the query for your application logs to look for requests the same URI and investigate further.
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://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
tags:
  analytic_story:
  - ConnectWise ScreenConnect Vulnerabilities
  asset_type: Web Server
  confidence: 100
  impact: 100
  message: An authentication bypass attempt against ScreenConnect has been detected on $dest$.
  mitre_attack_id:
  - T1190
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - Web.src
  - Web.dest
  - Web.http_user_agent
  - Web.url
  - Web.status
  - Web.http_method
  risk_score: 100
  security_domain: network
  cve:
  - CVE-2024-1708
  - CVE-2024-1709 
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1190/screenconnect/connectwise_auth_suricata.log
    sourcetype: suricata
    source: suricata