⚠️ WARNING THIS IS A EXPERIMENTAL DETECTION
We have not been able to test, simulate or build datasets for it, use at your own risk!
The following analytic identifies the usage of Exchange PowerShell modules that were recently used for a proof of concept related to ProxyShell. Currently, there is no active data shared or data we could re-produce relate to this part of the ProxyShell chain of exploits.
Inherently, the usage of the modules is not malicious, but reviewing parallel processes, and user, of the session will assist with determining the intent.
Module - New-MailboxExportRequest will begin the process of exporting contents of a primary mailbox or archive to a .pst file.
Module - New-managementroleassignment can assign a management role to a management role group, management role assignment policy, user, or universal security group (USG).
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2021-08-27
- Author: Michael Haag
- ID: 2d10095e-05ae-11ec-8fdf-acde48001122
`powershell` EventCode=4104 Message IN ("*New-MailboxExportRequest*", "*New-ManagementRoleAssignment*") | stats count min(_time) as firstTime max(_time) as lastTime by Path Message OpCode ComputerName User EventCode | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `exchange_powershell_module_usage_filter`
Associated Analytic Story
How To Implement
To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://docs.splunk.com/Documentation/UBA/22.214.171.124/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
Kill Chain Phase
Known False Positives
Administrators or power users may use this PowerShell commandlet for troubleshooting.
|15.0||30||50||Local user discovery enumeration using PowerShell on $dest$ by $user$|
source | version: 1