VLC And Secunia Fighting Over Vulnerability Reports

benjymouse writes "Following a blog post by security company Secunia, VideoLAN (vendor of popular VLC media player) president Jean-Baptiste Kempf accuses Secunia of lying in a blog post titled 'More lies from Secunia.' It seems that Secunia and Jean-Baptiste Kempf have different views on whether a vulnerability has been patched. At one point VLC threatened legal action unless Secunia updated their SA51464 security advisory to show the issue as patched. While Secunia changed the status pending their own investigation, they later reverted to 'unpatched.' Secunia claimed that they had PoC illustrating that the root issue still existed and 3rd party confirmation (an independent security researcher found the same issue and reported it to Secunia)." There are two bugs: one is a vulnerability in ffmpeg's swf parser that vlc worked around since they don't support swf. The VLC developers think Secunia should have reported the bug to ffmpeg, which seems pretty sensible. The other bug is an uncaught exception in the Matroska demuxer with overly large chunks that merely results in std::terminate being called; the Matroska demux maintainer apologized, but, despite dire warnings from Secunia that it could be exploitable, it most certainly is not.

Comments

I call my doctor...

[wbr1]

when I need to call std::terminate.

Re:You'd be surprised

[fnj]

What kind of things are exploitable.

Learn.

If the above involves a SEH chain to be invoked on windows it can be exploited.

It doesn't. C++ exceptions have exactly NOTHING to do with Win32 structured exceptions.

Re:Yet another biased Slashdot story

[Anonymous Coward]

Wow! You mean a dodgy video (or other media file) can cause a player to stop execution and end in a controlled manner. Fuck my old boots, the world will end tomorrow.

VLC over-priced? What planet are you on, it's a free in both senses of the word, you plank! If anyone is selling media playback, they'll simply put a wrapper over ffmpeg, like 99% of Windows and OSX video players do already.

Re:Put up or shut up

[Lunix Nutcase]

How is that phrase gibberish? It's quite clear what it means if you've ever used C++ and function pointers to implement callbacks for an object.

Re:Yet another biased Slashdot story

[g0bshiTe]

It's just important that if two attackers are at it that they don't cross the streams.

Re:... citation?

[dgatwood]

No citation needed. AFAIK, there are no known vectors for exploiting an uncaught exception, with two exceptions:

• If the exception itself causes some secret information to be leaked to a log file somewhere. This does not apply because the content being played is owned by the computer's owner, who also owns the log files.
• If the exception causes some component to get freed and you end up with a use-after-free situation (or it causes some process to die and some other process fails to handle that death in a safe manner). Presumably VLC is designed to handle codecs going away, but if not, then that is the exploitable vulnerability, not the exception itself.

Re:Yet another biased Slashdot story

[Sarten-X]

You jest, but that's a decent example. It's a hostile world, and every little thing, no matter how trivial, can be used against you, in unexpected ways. If you're aiming to kill a sysadmin, perhaps VLC is just the right tool for the job. Perhaps the bus hit was planned, and the attacker just needed a way to get the admin out in the open.

One of my personal favorite exploits involved using a core dump to drop a file into cron.d. The kernel, being ever so helpful, would put the dump into whatever working directory the crashing program was running in. Cron, being ever so helpful, would run all the files in cron.d, and being ever so helpful, would ignore all the badly-malformed data in those files. Put them together, and suddenly any user who can run a program can schedule commands to be run as root.

As your example shows with ample hyperbole, even a clean termination may be part of a larger plan. Perhaps VLC terminating triggers a watchdog that is differently-exploitable. Perhaps VLC is interfering with another exploit the attacker wants to use. Perhaps something else altogether... what matters is that all such attack vectors can be blocked by fixing this unexpected behavior.