Webserver HTTP Request Indicators for CVE-2020-0688 Exploitation Attempts

title: Webserver HTTP Request Indicators for CVE-2020-0688 Exploitation Attempts
id: 7e35a2ab-e97d-4563-806b-0a8167a2b459
status: test
description: This rule flags webserver requests whose URI query contains the Exchange OWA default page path along with __VIEWSTATEGENERATOR and __VIEWSTATE parameters. Attackers often probe or attempt exploitation by crafting requests that include these ASP.NET viewstate fields. The detection relies on webserver telemetry capturing the full URI query string (cs-uri-query) and matching required substrings within it.
references:
  - https://github.com/Ridter/cve-2020-0688
  - https://github.com/SigmaHQ/sigma/blob/master/rules-emerging-threats/2020/Exploits/CVE-2020-0688/web_cve_2020_0688_exchange_exploit.yml
author: NVISO, Huntrule Team
date: 2020-02-27
modified: 2023-01-02
tags:
  - attack.initial-access
  - attack.t1190
  - cve.2020-0688
  - detection.emerging-threats
logsource:
  category: webserver
detection:
  selection:
    cs-uri-query|contains|all:
      - /ecp/default.aspx
      - __VIEWSTATEGENERATOR=
      - __VIEWSTATE=
  condition: selection
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 7c64e577-d72e-4c3d-9d75-8de6d1f9146a
    type: derived