Remove Exported Mailbox from Exchange Webserver — Sigma Rule

Rule metadata and linked tags

Author: Christian Burkard (Nextron Systems). Source status: test; severity: high. Source dates: 2021-08-27 / 2023-01-23.

{
  "service": "msexchange-management",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 93d7a165b6055e5190313c883e733804ba4ace766632df0439b4726efd936641

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Remove Exported Mailbox from Exchange Webserver
id: 09570ae5-889e-43ea-aac0-0e1221fb3d95
status: test
description: Detects removal of an exported Exchange mailbox which could be to cover tracks from ProxyShell exploit
references:
    - https://github.com/rapid7/metasploit-framework/blob/1416b5776d963f21b7b5b45d19f3e961201e0aed/modules/exploits/windows/http/exchange_proxyshell_rce.rb#L430
author: Christian Burkard (Nextron Systems)
date: 2021-08-27
modified: 2023-01-23
tags:
    - attack.stealth
    - attack.t1070
logsource:
    service: msexchange-management
    product: windows
detection:
    keywords:
        '|all':
            - 'Remove-MailboxExportRequest'
            - ' -Identity '
            - ' -Confirm "False"'
    condition: keywords
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/rapid7/metasploit-framework/blob/1416b5776d963f21b7b5b45d19f3e961201e0aed/modules/exploits/windows/http/exchange_proxyshell_rce.rb#L430