17 Oct
2007
17 Oct
'07
12:13 p.m.
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) ?
Looking to get your thoughts-
-will
17 Oct
17 Oct
6:11 p.m.
At 18:13 17/10/2007, 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) ?
We have been thinking hard of this in the SER community. My 2 cents are that
sanitizing in the proxy is of limited impact. The trouble is that it is not
just JavaScript, it can be literally any application in any language, which
is tunneled some crafted data through SIP. The SIP proxy can be tought to
detect JavaScript but who knows what is going to come next. Thus I think
that JAva-Script enabled apps should test SER-produced data for Java-script
data, and XYZ-apps should test SER-produced data for XYZ-script data.
As an example, the latest serweb version, which uses JavaScript, is resistant
against such JavaScript attacks.
-jiri
Looking to get your thoughts-
-will
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--
Jiri Kuthan http://iptel.org/~jiri/
6:27 p.m.
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
_______________________________________________
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Users(a)openser.org
http://openser.org/cgi-bin/mailman/listinfo/users
8:27 p.m.
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(a)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(a)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(a)openser.org
http://openser.org/cgi-bin/mailman/listinfo/users
_______________________________________________
Users mailing list
Users(a)openser.org
http://openser.org/cgi-bin/mailman/listinfo/users 
18 Oct
18 Oct
4:41 a.m.
On Thursday 18 October 2007, Edson wrote:
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... ;)
Perhaps it makes more sense to use an IDS for this job, which already has the
infrastructure present to search in the traffic and match against arbitrary
rules. It can alert or kill the connection if something against the policy is
detected.
Cheers,
Henning
3:47 a.m.
William Quan schrieb:
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
Thats a cool attack. I fear there will be more smart attacks in the next
time.
klaus
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) ?
Looking to get your thoughts-
-will
_______________________________________________
Users mailing list
Users(a)openser.org
http://openser.org/cgi-bin/mailman/listinfo/users
10:26 a.m.
On 10/18/07 10:47, Klaus Darilion wrote:
William Quan schrieb:
cooler and cooler. My opinion is that the client should take care. I do
not see any reason why an application will interpret the display or user
name. It should be printed as it is. Same we can say may happen with the
email, when the text message will be interpreted, but not just
displayed. Would be funny to get compile errors or code executed when
someone just gives a snippet in a message.
AFAIK, unless is need for escape/unescape, those values should be taken
literally. Of course, having something in openser to detect/prevent
would be nice, but just as an add-on. Don't forget that some headers
bring nightmare after changing them -- although, in such cases, the
caller device won't care too much :)
Cheers,
Daniel
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
Thats a cool attack. I fear there will be more smart attacks in the
next time.
klaus
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) ?
Looking to get your thoughts-
-will
_______________________________________________
Users mailing list
Users(a)openser.org
http://openser.org/cgi-bin/mailman/listinfo/users
_______________________________________________
Users mailing list
Users(a)openser.org
http://openser.org/cgi-bin/mailman/listinfo/users
19 Oct
19 Oct
4:20 a.m.
At 16:26 18/10/2007, Daniel-Constantin Mierla wrote:
On 10/18/07 10:47, Klaus Darilion wrote:
'cos your phone has a webpage with received calls.
William Quan schrieb:
cooler and cooler. My opinion is that the client should take care. I do not see any
reason why an application will interpret the display or user name. 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
Thats a cool attack. I fear there will be more smart attacks in the next time.
It should be printed as it is. Same we can say may
happen with the email, when the text message will be interpreted, but not just displayed.
Would be funny to get compile errors or code executed when someone just gives a snippet in
a message.
AFAIK, unless is need for escape/unescape, those values should be taken literally. Of
course, having something in openser to detect/prevent would be nice, but just as an
add-on. Don't forget that some headers bring nightmare after changing them --
although, in such cases, the caller device won't care too much :)
possibly nice-to-have, but wasted effort IMO, see the previous email. something generally
app-unaware ('cos who knows what the actual app is) can't filter app, and attempts
to do
so always lag behind the attackers or break the apps.
-jiri
--
Jiri Kuthan http://iptel.org/~jiri/
6098
days inactive
6100
days old
7 comments
7 participants
participants (7)
-
Christian Schlatter -
Daniel-Constantin Mierla -
Edson -
Henning Westerholt -
Jiri Kuthan -
Klaus Darilion -
William Quan