Re[4]: DoS vulnerabilities in Firefox, Internet Explorer, Chrome, Opera and other browsers

From: Vladimir '3APA3A' Dubrovin <3APA3A@SECURITY.NNOV.RU>
To: John Smith <>
Cc: MustLive <>,Susan Bradley <>,
Subject: Re[4]: DoS vulnerabilities in Firefox, Internet Explorer, Chrome, Opera and other browsers

Dear John Smith,

 In  general  case  we  are  discussing,  DoS may be caused by e.g. some
 combination of allowed tags/properties or by malformed image.

 As  it  was  pointed  by  author,  this  attack  may  be performed with
 scripting  disabled  (with [iframe src=]). That's why e-mail vector may
 be significant.

--Friday, May 28, 2010, 11:55:28 PM, you wrote to 3APA3A@SECURITY.NNOV.RU:

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

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

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

JS> Done!

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

JS> --------------------------------------------------
JS> From: "Vladimir '3APA3A' Dubrovin" <3APA3A@SECURITY.NNOV.RU>
JS> Sent: Friday, May 28, 2010 11:47 PM
JS> To: "John Smith" <>
JS> Cc: "MustLive" <>; "Susan Bradley" 
JS> <>; <>
JS> Subject: Re[2]: DoS vulnerabilities in Firefox, Internet Explorer, Chrome,
JS> 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 
>> 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
>>    ,   .   . 
>> ()

Skype: Vladimir.Dubrovin
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