T1031.md

T1031 - Modify Existing Service

Description from ATT&CK

Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Registry. Service configurations can be modified using utilities such as sc.exe and [Reg](https://attack.mitre.org/software/S0075).

Adversaries can modify an existing service to persist malware on a system by using system utilities or by using custom tools to interact with the Windows API. Use of existing services is a type of Masquerading that may make detection analysis more challenging. Modifying existing services may interrupt their functionality or may enable services that are disabled or otherwise not commonly used.

Adversaries may also intentionally corrupt or kill services to execute malicious recovery programs/commands. (Citation: Twitter Service Recovery Nov 2017) (Citation: Microsoft Service Recovery Feb 2013)

Atomic Tests

• Atomic Test #1 - Modify Fax service to run PowerShell

Atomic Test #1 - Modify Fax service to run PowerShell

This test will temporarily modify the service Fax by changing the binPath to PowerShell and will then revert the binPath change, restoring Fax to its original state.

Supported Platforms: Windows

Run it with command_prompt! Elevation Required (e.g. root or admin)

sc config Fax binPath= "C:\windows\system32\WindowsPowerShell\v1.0\powershell.exe -noexit -c \"write-host 'T1031 Test'\""
sc start Fax
sc config Fax binPath= "C:\WINDOWS\system32\fxssvc.exe"