Hi Charles,
I can confirm that t_any_timeout(), and t_branch_timeout() return true when these un-ACKd transactions occur.
I just needed to make sure that I set a failure route, in my reply route.
Thanks for the tip.
On Tue, Apr 5, 2016 at 1:56 PM, Charles Chance < charles.chance@sipcentric.com> wrote:
Hi,
You should probably check out TM docs - specifically failure route ( http://kamailio.org/docs/modules/stable/modules/tm.html#tm.f.t_on_failure) and t_is_expired ( http://kamailio.org/docs/modules/stable/modules/tm.html#tm.f.t_is_expired ).
From there you can do what you like.
Cheers,
Charles On 5 Apr 2016 1:22 p.m., "Marrold" kamailio@marrold.co.uk wrote:
I am interested in 'fingerprinting' various SIP scanner attacks and using them to intelligently block attacks, rather than just blindly black listing any SIP message to a honey pot.
Additionally I think it would be wise to detect these missing ACKs and/or incomplete transactions from a legitimately mis-configured or malfunctioning end point, to help protect the core network from needless re-transmissions.
Having checked the Asterisk logs, this is what I'm looking to block if a certain threshold is exceeded-
[2016-04-05 13:10:52] WARNING[2010] chan_sip.c: Retransmission timeout reached on transmission eff430b8c1b6d21c2058049f41a7ec57 for seqno 1 (Critical Response)
Thanks
On Tue, Apr 5, 2016 at 1:14 PM, Daniel Tryba d.tryba@pocos.nl wrote:
On Tue, Apr 05, 2016 at 12:09:29AM +0100, Marrold wrote:
I have been running a couple of Asterisk honey pots to get a better understanding of the tools and methods potential hackers are using to exploit SIP servers.
I have observed many attacks from the 'sipcli' user agent that don't
send
ACKs.
[...]
Please could anyone point me in the right direction to detect these non completed calls with a missing ACK in Kamailio? I am unsure on the terminology I should be using to search the online documentation.
Why do you care? The attacker doesn't care about receiving SIP messages, they are only interested in initiating a call to a target, if the target gets dialled you will be abused, by either an other source with a fully function SIP stack or just something that might be spoofed.
What I do is blacklist addresses that send any SIP messages to my honeypots, might be dangerous since with UDP anything can be spoofed (so better make sure you have a whitelist and there is no connection between the honeypots and your client facing SIP platform)
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