Sitecore Pre-Auth RCE exploitation attempts via Report.ashx (CVE-2021-42237) on web servers

title: Sitecore Pre-Auth RCE exploitation attempts via Report.ashx (CVE-2021-42237) on web servers
id: 868059d5-b343-4653-9b41-5f2df4ef6f85
status: test
description: This rule flags HTTP POST requests that include the specific Report.ashx path under the Sitecore shell reporting endpoint and return a 200 status. Attackers may use this pre-auth remote code execution weakness to run code without authentication, making successful-looking responses particularly important. The detection relies on webserver HTTP logs capturing the request method, requested URI query content, and the resulting HTTP status code.
references:
  - https://blog.assetnote.io/2021/11/02/sitecore-rce/
  - https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1000776
  - https://github.com/SigmaHQ/sigma/blob/master/rules-emerging-threats/2021/Exploits/CVE-2021-42237/web_cve_2021_42237_sitecore_report_ashx.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2021-11-17
modified: 2023-01-02
tags:
  - attack.initial-access
  - attack.t1190
  - cve.2021-42237
  - detection.emerging-threats
logsource:
  category: webserver
detection:
  selection:
    cs-method: POST
    cs-uri-query|contains: /sitecore/shell/ClientBin/Reporting/Report.ashx
    sc-status: 200
  condition: selection
falsepositives:
  - Vulnerability Scanning
level: high
license: DRL-1.1
related:
  - id: 20c6ed1c-f7f0-4ea3-aa65-4f198e6acb0f
    type: derived