[VOIPSEC] [SearchSecurity.com] Better VoIP training needed, SANS director says

Simon Horne s.horne at packetizer.com
Sun Dec 10 19:34:08 GMT 2006


I totally agree, security is not a mainstream issue until it starts to 
become an issue, then of course it's all too late.

On the topic of IM have you had a chance to read my proposal and working 
document H.460.tm (Text Messaging)
It is completely backwards interoperable. You can have two softphone 
connected to an old cisco network and be able to exchange text messages 
between eachother.  Gives you something to think about :-)

>P.S. In H.323 haft of the bugs have been in ASN.1 parser, because that 
>protocol is too difficult to implement.

This is a kinda funny statement to make given you previous post on the 
topic..:-)  There are quite a few (as you know) very good ASN.1 parsers 
available in both open source and can be purchased. For instance it took me 
no more than about 5 minutes (serious) to upgrade my code from H.323v5 to 
H.323v6 using an open source ASN.1 C++ parser and ASN.1 definitions 
straight out of the standards documents. Once you have a decent parser then 
building is just a snap. Understanding how it all works is a different 
story. The protocol is extremely complicated (in some areas overly 
complicated) but it was designed to accommodate most requirements of a VoIP 
system including PSTN interoperability and security framework from the very 
beginning. Trying to add these features later on can be just as difficult 
or more difficult to implement.

I personally have used the existing security framework of H.323 to 
embedding digital certificates for authentication, diffie-hellmen keys for 
media encryption, caller credentials (username/password) for border call 
admission etc into pre-existing standard signalling messages and 
successfully deployed these devices interoperablity in pre-existing H.323 
networks. This isn't rocket science, if a flexible security framework 
exists than with a bit of effort it is possible, if it does not then 
securing that VoIP network, at best is difficult and potentially costly 
wholesale upgrading endeavor or at worst a worthless completely broken mess 
like email.


At 12:51 AM 11/12/2006, Diana Cionoiu wrote:
>Hello Simon,
>This is why we decided to support Jingle in Yate. Jingle has the advantage 
>that it has a mechanism that works against spam (the dialback system 
>existing in Jabber), better than any other VoIP protocol that i know, and 
>it also has support for IM, and gateways to the main existing networks, 
>and probably in the future we will be able to build gateways for audio.
>In the end i can say that i do hope for better networks, but security has 
>never been a mainstream issue, and i doubt it will become very soon. So 
>any protocol that wants to have a chance this days has to provide more 
>than security.
>Diana Cionoiu
>P.S. In H.323 haft of the bugs have been in ASN.1 parser, because that 
>protocol is too difficult to implement.
>Simon Horne wrote:
>>I have to agree with Richard, those on this list know there are currently 
>>functioning, workable VoIP solutions (and have been for many years) which 
>>have security built in from the get-go including SMA and H.323. You can't 
>>blame the programmer if the protocol he/she has to work with does not 
>>have the native capacity to support the required security the programmer 
>>is trying to program.  Its not the programmers fault.
>>Lets be honest. The market has chosen to adopt a protocol which is very 
>>difficult to secure (as it has no native security support itself). That 
>>choice may come back to haunt the entire industry.

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