Detection rules › Sigma
Exchange Exploitation CVE-2021-28480
Detects successful exploitation of Exchange vulnerability as reported in CVE-2021-28480
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | T1190 Exploit Public-Facing Application |
Rule body yaml
title: Exchange Exploitation CVE-2021-28480
id: a2a9d722-0acb-4096-bccc-daaf91a5037b
status: test
description: Detects successful exploitation of Exchange vulnerability as reported in CVE-2021-28480
references:
- https://twitter.com/GossiTheDog/status/1392965209132871683?s=20
author: Florian Roth (Nextron Systems)
date: 2021-05-14
modified: 2023-01-02
tags:
- attack.initial-access
- attack.t1190
- cve.2021-28480
- detection.emerging-threats
logsource:
category: webserver
detection:
selection:
cs-uri-query|contains: '/owa/calendar/a'
cs-method: 'POST'
filter_main_status:
sc-status: 503
condition: selection and not 1 of filter_*
falsepositives:
- Unknown
level: critical
Stages and Predicates
Stage 0: condition
selection and not 1 of filter_*Stage 1: selection
selection:
cs-uri-query|contains: '/owa/calendar/a'
cs-method: 'POST'
Stage 2: not filter_main_status
filter_main_status:
sc-status: 503
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
sc-status | eq | 503 |
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-method | eq |
|
cs-uri-query | match |
|