T1547.012 — Boot or Logon Autostart Execution: Print Processors
Sub-technique of T1547 Boot or Logon Autostart Execution
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.
Detected by EasySIEM
This project's own SigmaHQ-derived detection pipeline tags every compiled rule with the ATT&CK technique(s) it maps to -- if a rule in your install covers this technique, it shows up automatically on your own Grafana Alerts dashboard's "Top ATT&CK Techniques" panel, no lookup needed. This page exists so a click from there always lands here on easysiem.com, not on attack.mitre.org.