OWASSRF Exploitation Attempt Using Public POC - Proxy

title: OWASSRF Exploitation Attempt Using Public POC - Proxy
id: fdd7e904-7304-4616-a46a-e32f917c4be4
status: test
description: Detects exploitation attempt of the OWASSRF variant targeting exchange servers using publicly available POC. It uses the OWA endpoint to access the powershell backend endpoint
references:
    - https://www.crowdstrike.com/blog/owassrf-exploit-analysis-and-recommendations/
    - https://www.rapid7.com/blog/post/2022/12/21/cve-2022-41080-cve-2022-41082-rapid7-observed-exploitation-of-owassrf-in-exchange-for-rce/
    - https://twitter.com/purp1ew0lf/status/1602989967776808961?s=12&t=OkZJl_ViICeiftVEsohRyw
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-12-22
tags:
    - attack.initial-access
    - attack.t1190
    - detection.emerging-threats
logsource:
    category: proxy
detection:
    selection:
        # Look for the header: X-OWA-ExplicitLogonUser: owa/mastermailbox@outlook.com
        c-useragent: 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.5195.54 Safari/537.36'
        cs-method: 'POST'
        sc-status: 200
        c-uri|contains|all:
            - '/owa/mastermailbox'
            - '/powershell'
    condition: selection
falsepositives:
    - Unlikely
level: critical