Firefox wyciwyg:// cache zone bypass

Advisory Content :

There is an interesting vulnerability in how Mozilla Firefox handles
internal wyciwyg:// pseudo-URIs. These cache-related resource identifiers
are meant to be inaccessible by the user - but there are at least three
routes to bypass these restrictionss, one of which - HTTP 302 redirect -
also improperly employs same-domain policy checks.

This combo flaw enables attackers to intercept sensitive data, perform
cache poisoning, or carry out URL spoofing (including SSL certs), against
sites that scriptually render documents on client side, and hence produce
wyciwyg:// resources to begin with. Although not all sites are susceptible
to attacks, a good chunk of "Web 2.0", a selection of popular webmails,
and several major banks, very much are.

A quick demo and a more detailed discussion can be found here:

http://lcamtuf.coredump.cx/ffcache/

PS. The two remaining routes to bypass wyciwyg:// restrictions
(XMLHttpRequest() and view-source: URIs) appear to properly implement
same-domain checks (although view-source seems to be nevertheless not
functioning as intended). document.write() + XMLHttpRequest to wyciwyg://
URIs can be used by rogue websites to conveniently store and retrieve
persistent "markers" on visitor's machine regardless of cookie settings;
that's not a disaster, but still not very nice.

PS2. Bugzilla entry here - source patch available:
https://bugzilla.mozilla.org/show_bug.cgi?id=387333

Cheers!
/mz

Security

IT News

Search

SecurityAlert Database

About SecurityAlert

ExploitAlert Database

SecurityReason Research

WLB Database

Send to WLB

About WLB

Security Audit

Schedule

Prices of services

Contact

SecurityReason IT News

SecurityAlert

World Laboratory of Bugtraq

ExploitAlert

Apache

PHP

Contact

About SecurityReason

Firefox wyciwyg:// cache zone bypass