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Re: ASN.1 telephony critical infrastructure warning - VOIP




I would say that this is somewhat misleading. First of all not all VoIP services use ASN.1 encoding for the protocol. While H.323 does SIP does not.

Additionally I suspect that not many of the carrier deployment of H.323 are using the MS ASN.1 libs as most of them are unix based (many of them will be running SPARC/Solaris).

Now that being said if companies are allowing VoIP to the desktop for services like netmeeting there could be problems.

        RJ

---
RJ Auburn
CTO, Voxeo Corporation
tel:+1-407-418-1800


On Feb 17, 2004, at 07:37, Gadi Evron wrote:

I apologize, but I am using these mailing lists to try and contact the different */CERT teams for different countries.

As we all know, ASN.1 is a new very easy to exploit vulnerability. It attacks both the server and the end user (IIS and IE).

We expect a new massive worm to come out exploiting this vulnerability in the next few days.

Why should this all interest you beyond it being the next blaster?

ASN is what VOIP is based on, and thus the critical infrastructure for telephony which is based on VOIP.

This may be a false alarm, but you know how worms find their way into every network, private or public. It could (maybe) potentially bring the system down.

I am raising the red flag, better safe than sorry.

The two email messages below are from Zak Dechovich and myself on this subject, to TH-Research (The Trojan Horses Research Mailing List). The original red flag as you can see below, was raised by Zak. Skip to his message if you like.

    Gadi Evron.



Subject: [TH-research] */CERT people: Critical Infrastructure and ASN.1 - VOIP [WAS: Re:
 [TH-research] OT: naming the fast approaching ASN.1 worm]

Mail from Gadi Evron <ge@xxxxxxxxxxxx>

All the */CERT people on the list:
If you haven't read the post below, please do.

Anyone checked into the critical infrastructure survivability of an ASN
worm hitting? phone systems could possibly go down. We all know how
worms find their way into any network, private or otherwise. and VOIP
systems (which phone systems are based on nowadays) could go down.

Heads-up! Finds them contingency plans..  :o)

Any information would be appreciated, or if you need more information from us: +972-50-428610.

    Gadi Evron.


Zak Dechovich wrote:

> Mail from Zak Dechovich <ZakGroups@xxxxxxxxxxxx>
>
> May I suggest the following:
>
> ASN1 is mainly used for the telephony infrastructure (VoIP),
> any code that attacks this infrastructure can be assigned with 'VoIP'
> prefix, followed by the attacked vendor (cisco, telrad, microsoft, etc.).
>
> for example, if (when) Microsoft's h323 stack will be attacked, the name > should be VoIP.ms323.<variant>, or if Cisco's gatekeepers will crash, lets
> call it VoIP.csgk.<variant>
>
> Your thoughts ?
>
> Zak Dechovich,
>
> Zak Dechovich,
> Managing Director
> SecureOL Ltd.
> Mobile: +972 (53) 828 656
> Office: +972 (2) 675 1291
> Fax:    +972 (2) 675 1195

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