Date: Mon, 17 Sep 2012 19:22:03 -0600 From: Kurt Seifried <kseifried@...hat.com> To: oss-security@...ts.openwall.com CC: Raphael Geissert <geissert@...ian.org>, argyros george <argyros.george@...il.com>, Aggelos Kiayias <aggelos@...yias.com>, Vladimir Vorontsov <vladimir.vorontsov@...ec.ru>, gifts <gifts.antichat@...il.com> Subject: Re: Randomness Attacks Against PHP Applications -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 09/17/2012 10:58 AM, Raphael Geissert wrote: > 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.) Agreed. One example of a similar problem with good images displaying the issue clearly: http://lcamtuf.coredump.cx/newtcp/ > 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, > - -- Kurt Seifried Red Hat Security Response Team (SRT) PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQIcBAEBAgAGBQJQV8y7AAoJEBYNRVNeJnmTMsYP/jMjcOslDu6l8aoxpSqNcFmB hdRaVRNxBh3A/IK0Vg0syR1vmP8ShFlJCEZ9XUc+8v0E/s75EO6fWNsntKTSZY5s A646R13ENc46aPhBi2feO7PX/bVTsJVvwVMMrKLlwTWIGoyfbemAjkWRE5VBwr6x U+R1tp97wpK65LGjwmImgzCJMUqBXGuemm+jpJTMBltcACKvGp7h28wfJL66UR76 mSV0F7YisjZ3gKHv5DmKxlzVRNx9KcKM3qaMjWVuAIicMz3CBsbJ68WXVRbraV0Q dXtkh5Uo/dfnfjXC6rPAMwkqOb7tdIB076alxTq16C2hbXrUVgroysJ4C4v16XTk qkZOH6jcZYWiQai/tDQA/DNAsKbBTNj8N6JRX7y1i0d8l1SGv+fbGtG2qTeZEs5R XhoVxKpEQUWrEU5yi7ToVasjqXUrE4cvD3n6RUX0s6IODjbm6Zbow/+F4PWIFJWF wr2GC9nGn3RKicLxi+/mUWgtukZljfneYJu0i+R9DPDjwd0IxgpaWre3c//JurK5 AVX9clRdEEUZD4chzqDRdzv2xmJLDcevOo29s2XC8DzePWGRO+D7t+RhQkQ4C7JB AaZyGKCr9tosPKUVWm7UGIAWxvHaIBsvfcH6V+lGSMkeyCIeAYFV+cWjgP/aZnno Xeicv9GFtZPRw5ThRyFi =D8kI -----END PGP SIGNATURE-----
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