[asterisk-users] SIP Blacklisting

[Zeeshan Zakaria]

I was thinking on the same lines, i.e. setup a server which will be
regularly updated with these bad IP addresses, and anybody looking to block
bad IPs will be able to get this list from here. For example when I get mail
from Fail2Ban (which I am getting more and more everyday now), a copy would
be sent to this server with the updated bad IP address.

But the problem is how to make sure that only legitimate users are
contributing to this list. Contributors to this list somehow need to verify
to an admin that they are not hackers, and this the hard part.

Zeeshan A Zakaria

--
www.ilovetovoip.com

On 2010-10-21 11:46 AM, "Steve Howes" <steve-lists at geekinter.net> wrote:

Hi,

Given the recent increase in SIP brute force attacks, I've had a little
idea.

The standard scripts that block after X attempts work well to prevent you
actually being compromised, but once you've been 'found' then the attempts
seem to keep coming for quite some time. Older versions of sipvicious don't
appear to stop once you start sending un-reachables (or straight drops). Now
this isn't a problem for Asterisk, but it does add up in (noticeable)
bandwidth costs - and for people running on lower bandwidth connections. The
tool to crash sipvicious can help this, but very few attackers seem to obey
it..

The only way I can see to alleviate this, is to blacklist hows *before* they
attack. This means you wont ever be targeted past an initial scan.

Is there any interest in a 'shared' blacklist (similar to spam blacklists,
but obviously implemented in a way that is more usable with
Asterisk/iptables)?. Clearly it raises issues about false positives etc, but
requiring reports from more than X hosts should alleviate this. There's all
the usual de-listing / false-listing worries as with any blacklist, but the
SMTP world has solutions we could learn from.

Leaving a 'honeypot' running on a single IP address has revealed a few
hundred addresses in less than a month. I am fairly certain these are all
'bad' as this host isn't used for anything else. There is obviously a wealth
of data (and attacks) out there that would be good to share.

Anyone have any thoughts?

S
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