Re: Re[2]: DoS vulnerabilities in Firefox, Internet Explorer, Chrome, Opera and other browsers

["John Smith" <at-x () live com>]

Point taken. But that'd be a non-issue on the browser's end as much as 
site's that is allowing the rogue scripts (or malformed ads, as per your 
example).
The fork of this mail thread clearly explains what I'm talking about. The 
issue noted there is a simple DoS attack which every programming language 
and platform is vulnerable too. Its called the "infinite loop". It is not a 
'security vulnerability' by itself and is completely agnostic of the uri 
handler (try http or anything instead of nntp).

Here's the simplified JS version of it (lets call it the Universal DoS --  
yes, it'd work for every browser on the planet that can execute JS) -

<script>
while(1)alert('hello world');
</script>

Done!

Workaround:
None very intuitive. Maybe allow the user to terminate the script at every 
iteration? specific time period? etc...

--------------------------------------------------
From: "Vladimir '3APA3A' Dubrovin" <3APA3A () SECURITY NNOV RU>
Sent: Friday, May 28, 2010 11:47 PM
To: "John Smith" <at-x () live com>
Cc: "MustLive" <mustlive () websecurity com ua>; "Susan Bradley" 
<sbradcpa () pacbell net>; <bugtraq () securityfocus com>
Subject: Re[2]: DoS vulnerabilities in Firefox, Internet Explorer, Chrome, 
Opera and other browsers

> Dear John Smith,
>
> Actually,  browser DoS may be quite serious vulnerability, depending on
> nature  of  DoS.  Think  about e.g. banner or content exchange network,
> social  networks,  web  boards,  etc where browser vulnerability may be
> used  against  site  or  page because it will harm any visitors of this
> site or page.
>
> In  case  of  this  very vulnerability, most serious impact may be from
> e-mail vector.
>
> --Friday, May 28, 2010, 7:07:50 PM, you wrote to 
> mustlive () websecurity com ua:
>
> JS> Just a few cents - DoS in webbrowsers doesn't fall under the category 
> of
> JS> "vulnerabilities" rather more of "annoyances". Although I don't deny 
> the
> JS> fact that certain DoS attacks *may lead* or *may serve as hints* to 
> other
> JS> more serious exploits, but that's a different topic and with ASLR in 
> the
> JS> scene, a very grey area of discussion.
>
>
>
> --
> Skype: Vladimir.Dubrovin
> ~/ZARAZA http://securityvulns.com/
> Стреляя во второй раз, он искалечил постороннего. Посторонним был я. 
> (Твен)