Modify Process (not services) Level Permissions via command line (Windows) - to make process interminable by non admin user

Question

Goal:

On my PC, there is a background script (Process A) that runs on startup with Administrator Level Permissions on the Standard Level Account (Account X). I would like to use this script, with it's elevated permissions to modify the process-level permissions on a process (Process B) that is run by Account X on startup.

The goal is to make Process B interminable by Account X, whilst still being initiated by Account X.

Background:

This is easily achievable with Process Explorer, but this is a GUI program. There is some material online regarding changing permissions via command line, but these are for services, not for processes.

Specifically, I need to add Deny Permissions on Terminate Process, and Change Permissions to Account X for Process B.

Summary:

• Process A is started up on login (into Account X) via Task Scheduler running under an Administrator Account
• Process B is started up by Account X
• Account X is a standard level account
• I can use Process Explorer to manually add the Deny Permissions I am describing, but I want Process A to do it itself (perhaps by command line).

Answer 1

A program running with Administrator permissions can modify a process ACL to remove PROCESS_TERMINATE permission.

An example written in C++ found in this post:

static const bool ProtectProcess()
{
    HANDLE hProcess = GetCurrentProcess();
    EXPLICIT_ACCESS denyAccess = {0};
    DWORD dwAccessPermissions = GENERIC_WRITE|PROCESS_ALL_ACCESS|WRITE_DAC|DELETE|WRITE_OWNER|READ_CONTROL;
    BuildExplicitAccessWithName( &denyAccess, _T("CURRENT_USER"), dwAccessPermissions, DENY_ACCESS, NO_INHERITANCE );
    PACL pTempDacl = NULL;
    DWORD dwErr = 0;
    dwErr = SetEntriesInAcl( 1, &denyAccess, NULL, &pTempDacl );
    // check dwErr...
    dwErr = SetSecurityInfo( hProcess, SE_KERNEL_OBJECT, DACL_SECURITY_INFORMATION, NULL, NULL, pTempDacl, NULL );
    // check dwErr...
    LocalFree( pTempDacl );
    CloseHandle( hProcess );
    return dwErr == ERROR_SUCCESS;
}

More questions about this code should rather be asked on StackOverflow.