oss-sec mailing list archives

Re: Randomness Attacks Against PHP Applications


From: Yves-Alexis Perez <corsac () debian org>
Date: Fri, 10 Aug 2012 10:56:24 -0700

On jeu., 2012-08-09 at 11:19 -0700, Yves-Alexis Perez wrote:
Hi list,

I'm currently at the Usenix Security 2012 conference, where there was a
nice paper about randomness vulnerabilities in PHP applications. I
invite you to read the paper[1] but in summary, a lot of PHP
applications make false assumption about the true randomness of the core
PHP random functions and it might lead to attacks, for example using the
“password reset” features.

Paper authors tried to port this to PHP security team, but it seems the
answer was that it was an application problem. Some examples are given
in the paper, but I have no idea where exactly the vulnerabilities
really lie. The various rand() functions used by application developers
might just not hold up to the expectations, or the developers might just
don't know that they should use a cryptographically secure random
function.

In any case, I guess some discussion might be needed on how to really
fix those vulnerabilities, and here seems like a good place. I've just
added the two papers authors to CC:, but it might be interesting to
bring PHP security team and applications developers in the loop.

 ven., 2012-08-10 at 09:57 -0700, Aggelos Kiayias wrote:
Hi Yves-Alexis -

my student George Argyros brought the below to my attention - (but I  
have not received any e-mail myself - )

Sorry, I tried to add you to CC: of the initial mail but it seems I
failed

thanks for taking this initiative - I think it is important to find  
the optimal way to resolve these problems and
relying on web application developers to have the expertise to
resolve  
these problems on their side is totally unrealistic. 

To be honest, I don't have any position on this. I was merely forwarding
your work to raise awareness on this list, but I have no idea what's the
correct way to move forward.

Regards,
-- 
Yves-Alexis

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