t1547-012-print-processors

name	T1547.012_print-processors
description	Adversaries may abuse print processors to run malicious DLLs during system boot for persistence and/or privilege escalation.
category	configuration
version	18.1
author	cyberstrike-official
tags	["mitre-attack","enterprise","t1547.012","persistence","privilege-escalation","windows","sub-technique"]
technique_id	T1547.012
tactic	persistence
all_tactics	["persistence","privilege-escalation"]
platforms	["Windows"]
mitre_url	https://attack.mitre.org/techniques/T1547/012
tech_stack	["windows"]
cwe_ids	["CWE-276"]
chains_with	["T1547","T1547.001","T1547.002","T1547.003","T1547.004","T1547.005","T1547.006","T1547.007","T1547.008","T1547.009","T1547.010","T1547.013","T1547.014","T1547.015"]
prerequisites	["T1547"]
severity_boost	{"T1547":"Chain with T1547 for deeper attack path","T1547.001":"Chain with T1547.001 for deeper attack path","T1547.002":"Chain with T1547.002 for deeper attack path"}

T1547.012 Print Processors

Sub-technique of: T1547

High-Level Description

Adversaries may abuse print processors to run malicious DLLs during system boot for persistence and/or privilege escalation. Print processors are DLLs that are loaded by the print spooler service, spoolsv.exe, during boot.

Adversaries may abuse the print spooler service by adding print processors that load malicious DLLs at startup. A print processor can be installed through the AddPrintProcessor API call with an account that has SeLoadDriverPrivilege enabled. Alternatively, a print processor can be registered to the print spooler service by adding the HKLM\SYSTEM\[CurrentControlSet or ControlSet001]\Control\Print\Environments\[Windows architecture: e.g., Windows x64]\Print Processors\[user defined]\Driver Registry key that points to the DLL.

For the malicious print processor to be correctly installed, the payload must be located in the dedicated system print-processor directory, that can be found with the GetPrintProcessorDirectory API call, or referenced via a relative path from this directory. After the print processors are installed, the print spooler service, which starts during boot, must be restarted in order for them to run.

The print spooler service runs under SYSTEM level permissions, therefore print processors installed by an adversary may run under elevated privileges.

Kill Chain Phase

• Persistence (TA0003)
• Privilege Escalation (TA0004)

Platforms: Windows

What to Check

• Identify if Print Processors technique is applicable to target environment
• Check Windows systems for indicators of Print Processors
• Verify mitigations are bypassed or absent (1 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Atomic Red Team Tests

The following tests are from Atomic Red Team and provide actionable ways to test this technique:

Atomic Test 1: Print Processors

Establishes persistence by creating a new print processor registry key under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Environments\Windows x64\Print Processors. The new print processor will point to a DLL which will be loaded by the spooler service after a reboot. The DLL will then create the file AtomicTest.txt in C:\Users\Public\ as validation that the test is successful.