Sigma Rule Library

Fortinet CVE-2021-22123 Exploitation

Detects CVE-2021-22123 exploitation attempt against Fortinet WAFs

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Detection logic

selection

cs-uri-query|contains: /api/v2.0/user/remoteserver.saml
cs-method: POST

filter1

cs-referer|contains: /root/user/remote-user/saml-user/

filter2

cs-referer: null

Condition

selection and not filter1 and not filter2

Raw YAML

title: Fortinet CVE-2021-22123 Exploitation
id: f425637f-891c-4191-a6c4-3bb1b70513b4
status: test
description: Detects CVE-2021-22123 exploitation attempt against Fortinet WAFs
references:
    - https://www.rapid7.com/blog/post/2021/08/17/fortinet-fortiweb-os-command-injection
author: Bhabesh Raj, Florian Roth
date: 2021-08-19
modified: 2023-01-02
tags:
    - attack.initial-access
    - attack.t1190
    - cve.2021-22123
    - detection.emerging-threats
logsource:
    category: webserver
detection:
    selection:
        cs-uri-query|contains: '/api/v2.0/user/remoteserver.saml'
        cs-method: POST
    filter1:
        cs-referer|contains: '/root/user/remote-user/saml-user/'
    filter2:
        cs-referer: null
    condition: selection and not filter1 and not filter2
falsepositives:
    - Unknown
level: critical

False positives

  • Unknown

References

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