[OpenSIPS-Users] SIP Authentication Attacks

[James Lamanna]

Hi,
I've noticed lately that a server of mine is getting repeatedly hit by
an attacker trying to make international calls.
The scary part is that the attacker seems to be able to register
correctly on different extensions, even though each extension has a
different, random password.
I'm not sure how the attacker is getting the passwords or if there's a
man-in-the-middle attack going on, but I would like some suggestions
on how to increase the security of SIP authentication in opensips.
I could enforce security through IP addresses, but I fear that will
become quite cumbersome.

Thanks.

-- James