oss-sec mailing list archives
Re: Randomness Attacks Against PHP Applications
From: Raphael Geissert <geissert () debian org>
Date: Mon, 17 Sep 2012 11:58:20 -0500
On Monday 17 September 2012 10:36:46 Josh Bressers wrote:
On Wed, Aug 22, 2012 at 02:31:07PM +0400, Solar Designer wrote: Maybe these PoCs will help convince someone.
Just a note regarding the sessionid case: IIRC since 5.4 session.entropy_length is set to, erm, 32 (bytes.) Basically it appends N bytes from /dev/urandom to the other input for the digest and then it is computed. (why 32 bytes, and why still use md5 by default, well...)
I'm skeptical they will. I've been doing a lot of work for the past year on various proactive security efforts. I keep coming back to two basic things.
[...]
Has anyone tried to talk to them about this further to see if the issue is they don't understand, or are they being stubborn?
I think the main problem is education. For instance, there is no word about mt_rand not being suitable for criptographic pourposes (much less what that means.) Sure, searching for "crypt" in the page shows a few comments saying that it isn't suitable, but: a) there are far more "encryption functions", "random password generators", and similar stuff in the comments than those that do mention its weaknesses. b) the official documentation itself doesn't say a word. It should say it loud and clear. Comments should also be moderated. Many examples available as comments in the documentation are incorrect. Now, pointing it out is easy, but somebody has to actually do the work. *That* is another issue. Cheers, -- Raphael Geissert - Debian Developer www.debian.org - get.debian.net
Current thread:
- Randomness Attacks Against PHP Applications Yves-Alexis Perez (Aug 09)
- Re: Randomness Attacks Against PHP Applications Yves-Alexis Perez (Aug 10)
- Re: Randomness Attacks Against PHP Applications Solar Designer (Aug 22)
- Re: Randomness Attacks Against PHP Applications Solar Designer (Sep 14)
- Re: Randomness Attacks Against PHP Applications Josh Bressers (Sep 17)
- Re: Randomness Attacks Against PHP Applications Raphael Geissert (Sep 17)
- Re: Randomness Attacks Against PHP Applications Daniel Kahn Gillmor (Sep 17)
- Re: Randomness Attacks Against PHP Applications Kurt Seifried (Sep 17)
- Re: Randomness Attacks Against PHP Applications George Argyros (Sep 20)
- Re: Randomness Attacks Against PHP Applications Solar Designer (Sep 22)
- Re: Randomness Attacks Against PHP Applications Vladimir Vorontsov (Sep 23)
- Re: Randomness Attacks Against PHP Applications George Argyros (Sep 27)
- Re: Randomness Attacks Against PHP Applications Raphael Geissert (Sep 24)
- Re: Randomness Attacks Against PHP Applications George Argyros (Sep 27)
- Re: Randomness Attacks Against PHP Applications Solar Designer (Sep 14)
- Re: Randomness Attacks Against PHP Applications Vladimir Vorontsov (Sep 17)