Created the Monday 18 March 2019. Updated 3 years, 6 months ago.

This function is undocumented within OpenProcess. It can be used to get the PID of CRSS.exe, which is a SYSTEM process. By default, a process has the SeDebugPrivilege privilege in their access token disabled.

However, when the process is loaded by a debugger such as OllyDbg or WinDbg, the SeDebugPrivilege privilege is enabled. If a process is able to open CRSS.exe process, it means that the process SeDebugPrivilege enabled in the access token, and thus, suggesting that the process is being debugged.

If we call OpenProcess and pass the ID returned by CsrGetProcessId, no error will occur if the SeDebugPrivilege has been set with SetPrivilege / AdjustTokenPrivileges.

Technique Identifier


Technique Tag


Code Snippets

#include <stdio.h>
#include <windows.h>
typedef HANDLE (*_CsrGetProcessId)();

int main(void)
    HMODULE nt=GetModuleHandle("ntdll.dll");
    _CsrGetProcessId CsrGetProcessId=(_CsrGetProcessId)GetProcAddress(nt,"CsrGetProcessId");
    HANDLE proc = OpenProcess(PROCESS_ALL_ACCESS,FALSE,CsrGetProcessId());

        printf("debugger is present!");

Detection Rules

rule Detect_CsrGetProcessID: AntiDebug {
        description = "Detect CsrGetProcessID as anti-debug"
        author = "Unprotect"
        comment = "Experimental rule"
        $1 = "CsrGetProcessID" fullword ascii
        $2 = "GetModuleHandle" fullword ascii
       uint16(0) == 0x5A4D and filesize < 1000KB and 2 of them 

Additional Resources

External Links

Subscribe to our Newsletter

The information entered into this form is mandatory. It will be subjected to computer processing. It is processed by computer in order to support our users and readers. The recipients of the data will be : contact@unprotect.it.

According to the Data Protection Act of January 6th, 1978, you have at any time, a right of access to and rectification of all of your personal data. If you wish to exercise this right and gain access to your personal data, please write to Thomas Roccia at contact@unprotect.it.

You may also oppose, for legitimate reasons, the processing of your personal data.