Re: Internet Explorer and Opera local zone restriction bypass

[Andreas Sandblad <sandblad@acc.umu.se>]

I can only reproduce it together with user-interaction, that is
manually pressing refresh in Internet Explorer. I did some attempts to
try to automaticly refresh the page using javascript but without any luck
(denied access due to cross-site-policy).

If this vulnerability depends both on manually pressing refresh and
knowing the username of the person visiting the malicious page (exact
path to known local file), then actual exploitation becomes much harder.

Environment: Latest fully patched IE on Win 2000 pro.

/Andreas Sandblad

On Fri, 24 Oct 2003, Mindwarper * wrote:

> Internet Explorer and Opera local zone restriction bypass.
> =--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=
>
> ----------------------
> Vendor Information:
> ----------------------
>
> Homepage : http://www.microsoft.com
> Vendor : informed
> Mailed advisory: 23/10/03
> Vender Response : None yet
>
>
> ----------------------
> Affected Versions:
> ----------------------
>
> All version of IE 6
> Possibly 5.x too
>
>
> ----------------------
> Description:
> ----------------------
>
> Microsoft Internet Explorer does not allow local file access by a remote host 
> by default.
> By creating an iframe which points on a specially crafted cgi script (using 
> the location header
> to confuse IE), it is possible to cause IE to execute any local file through 
> the iframe with local
> zone restrictions. This then allows remote arbitrary file execution on the 
> victim without having
> the victim do a thing except load the page.
> Opera seems to not only be affected by this vulnerability, but it also allows 
> direct
> local file access through iframes without any cgi scripts. Unlike IE where it 
> is possible
> to set activex objects to execute arbitrary files, in Opera it is not. There 
> may be a way,
> but I am currently not aware of any.
>
>
> ----------------------
> Exploit:
> ----------------------
>
> I have created a proof of concept page, but I did not show or explain how the 
> cgi scripts
> nor the flash file work exactly to prevent kiddie abuse.
>
> For IE: http://www.mlsecurity.com/ie/ie.htm
>
> For Opera: <iframe name="abc" src="file:///C:/"></iframe>
>
> ----------------------
> Solution:
> ----------------------
>
> Check Microsoft's website frequently until a new patch comes out.
>
> ----------------------
> Contact:
> ----------------------
>
> - Mindwarper
> - mindwarper@linuxmail.org
> - http://mlsecurity.com
>
>

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