I was thinking about this problem and I think that combining this module idea with the ones presented by Jiri could guide to an intermediary and more flexible one.
Any sanitization task would be processed by a dedicated module. This module could load as many 'sanitizations descriptions' as desired. Each 'sanitization description' could be a XML file (just to give an exemple) and would take care of an especific language or language family. It could describe signatures, or even include language syntax and semantics checks (who knows what is really necessary?). This way, changing/improving the descriptions with language specific sanitization knownledge would extended the protection without the need of logical changes on the proxy script.
For sure even if the idea is easy to understand it's implementation is not a trivial work. But is an idea... ;)
Edson
-----Original Message----- From: users-bounces@openser.org [mailto:users-bounces@openser.org] On Behalf Of Christian Schlatter Sent: quarta-feira, 17 de outubro de 2007 20:27 To: William Quan Cc: users@openser.org Subject: Re: [OpenSER-Users] sanitizing sip requests
William Quan wrote:
Hi all, I came across a security alert that basically embeds javascript in the display name of the From to initiate cross-site-scripting (XSS) attacks. Here is an example:
From: "<script>alert('hack')</script>""user" <sip:user at domain.com <https://lists.grok.org.uk/mailman/listinfo/full-
disclosure>>;tag=002a000c
Grammatically , I don't see an issue with this. However, under the right circumstances this could get ugly. Do you see value in having openser take a proactive role to detect these and reject calls? Or is this outside the scope of what a proxy should be doing (leave it to the UA to sanitize) ?
I think it should be left to the UA. It would be very difficult to come up with good sanitizing rules, and they would get out of data very quickly. Maybe an openser sanitizer module that would download SIP attack signatures would make sense.
/Christian
Looking to get your thoughts- -will
Users mailing list Users@openser.org http://openser.org/cgi-bin/mailman/listinfo/users
Users mailing list Users@openser.org http://openser.org/cgi-bin/mailman/listinfo/users