Exchange Set OabVirtualDirectory ExternalUrl Property

Rule to detect an adversary setting OabVirtualDirectory External URL property to a script in Exchange Management log

Sigma rule (View on GitHub)

 1title: Exchange Set OabVirtualDirectory ExternalUrl Property
 2id: 9db37458-4df2-46a5-95ab-307e7f29e675
 3status: test
 4description: Rule to detect an adversary setting OabVirtualDirectory External URL property to a script in Exchange Management log
 5references:
 6    - https://twitter.com/OTR_Community/status/1371053369071132675
 7author: Jose Rodriguez @Cyb3rPandaH
 8date: 2021-03-15
 9modified: 2023-01-23
10tags:
11    - attack.persistence
12    - attack.t1505.003
13logsource:
14    product: windows
15    service: msexchange-management
16detection:
17    keywords:
18        '|all':
19            - 'Set-OabVirtualDirectory'
20            - 'ExternalUrl'
21            - 'Page_Load'
22            - 'script'
23    condition: keywords
24falsepositives:
25    - Unknown
26level: high

References

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