Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 3 Oct 2008 22:18:48 +0200
From: Nico Golde <oss-security+ml@...lde.de>
To: oss-security@...ts.openwall.com
Subject: Re: regarding CVE-2008-4382 & CVE-2008-4381

Hi Steven,
* Steven M. Christey <coley@...us.mitre.org> [2008-10-03 22:15]:
> On Fri, 3 Oct 2008, Nico Golde wrote:
> 
> > looking at the PoC this would work in every browser
> > supporting JavaScript as this is just a trivial memory
> > consumption issue by passing a very large string too the
> > alert function and thus eating memory, a simple
> > while(true){} would be equally effective for eating cpu
> > cycles which I wouldn't consider as a vulnerability
> > either...
> 
> I usually wouldn't call it a vulnerability, either.  However, based on our
> analysis, the String.fromCharCode(550) creates a Unicode string for
> character 550, but the escape() for URL encoding can only cover 0 to 255,
> so it seemed like something else was going on here, maybe the alert
> function not working.
> 
> I don't know how Javascript manages large strings, but it seems like
> somewhere around the "x4 += x4;" statement, you exceed multiple gigs.  So
> maybe the alert function isn't even being reached...

I tested this already using a lower loop count in the for 
loops and got similar behaviour and saw the alert box.

Cheers
Nico
-- 
Nico Golde - http://www.ngolde.de - nion@...ber.ccc.de - GPG: 0x73647CFF
For security reasons, all text in this mail is double-rot13 encrypted.

Content of type "application/pgp-signature" skipped

Powered by blists - more mailing lists

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.