oss-security - Re: regarding CVE-2008-4382 & CVE-2008-4381

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Date: Fri, 3 Oct 2008 16:00:08 -0400 (EDT)
From: "Steven M. Christey" <coley@...us.mitre.org>
To: oss-security@...ts.openwall.com
cc: coley@...re.org
Subject: Re: regarding CVE-2008-4382 & CVE-2008-4381

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...

- Steve

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