[Kamailio-Users] SIP Digest Access Authentication RELAY survey

[Klaus Darilion]

Hi!

For those who are interested in this attack - I have attached the 
relevant slides from my SIP security lectures.

regards
Klaus

PS: an exploit based on sipp scenario files is available too on request 
(for educational purposes :-)



Klaus Darilion schrieb:
> IIRC to solve this issue completely the UAC should never send 
> credentials to unknown parties - only to its SIP proxy (some clients 
> have a "force outbound proxy" feature which does the same). Then the SIP 
> proxy can remove credentials before forwarding to other parties.
> 
> As soon as a client send messages (with credentials) directly to other 
> parties there is nothing you can do on the proxy side.
> 
> regards
> klaus
> 
> Victor Pascual Ávila schrieb:
>> Hi,
>> excuse me if this message is not directly related to Kamailio.
>>
>> I'm just wondering if folks could share with me if (and how) they have
>> prevented the "SIP Digest Access Authentication RELAY" in their
>> networks (and what worked for them or not).
>> NAT boxes reduce dramatically the scenarios for a successful attack.
>> Otherwise, some might be mitigating the attack by means of forcing UAs
>> to use outbound proxies while others might be reducing the attack
>> incentives by means of message integrity.
>>
>> Any comment would be appreciated,
> 
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