Detection rules › Sigma
Successful Exchange ProxyShell Attack
Detects URP patterns and status codes that indicate a successful ProxyShell exploitation attack against Exchange servers
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | No specific technique |
Rule body yaml
title: Successful Exchange ProxyShell Attack
id: 992be1eb-e5da-437e-9a54-6d13b57bb4d8
status: test
description: Detects URP patterns and status codes that indicate a successful ProxyShell exploitation attack against Exchange servers
references:
- https://youtu.be/5mqid-7zp8k?t=2231
- https://blog.orange.tw/2021/08/proxylogon-a-new-attack-surface-on-ms-exchange-part-1.html
- https://peterjson.medium.com/reproducing-the-proxyshell-pwn2own-exploit-49743a4ea9a1
author: Florian Roth (Nextron Systems), Rich Warren
date: 2021-08-09
modified: 2023-01-02
tags:
- attack.initial-access
- detection.emerging-threats
logsource:
category: webserver
detection:
selection_auto:
cs-uri-query|contains: '/autodiscover.json'
selection_uri:
cs-uri-query|contains:
- '/powershell'
- '/mapi/nspi'
- '/EWS'
- 'X-Rps-CAT'
selection_success:
sc-status:
- 200
- 301
condition: selection_auto and selection_uri and selection_success
falsepositives:
- Unknown
level: critical
Stages and Predicates
Stage 0: condition
selection_auto and selection_uri and selection_successStage 1: selection_auto
selection_auto:
cs-uri-query|contains: '/autodiscover.json'
Stage 2: selection_uri
selection_uri:
cs-uri-query|contains:
- '/powershell'
- '/mapi/nspi'
- '/EWS'
- 'X-Rps-CAT'
Stage 3: selection_success
selection_success:
sc-status:
- 200
- 301
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
cs-uri-query | match |
|
sc-status | eq |
|