Understanding Log Entry


Can someone help me understand these log entries:

[2020-03-30 04:48:21] ERROR[9722] pjproject: sip_transport.c Error processing 393 bytes packet from UDP : PJSIP syntax error exception when parsing 'Contact' header on line 8 col 10:
REGISTER sip:xxx.xxx.xxx.xxx SIP/2.0
Via: SIP/2.0/UDP;branch=z9hG4bK-2271119571;rport
Max-Forwards: 70
To: "Grandstream"<sip:[email protected]>
From: "Grandstream"<sip:[email protected]>;tag=3935316334303662313363340132353136393534313836
User-Agent: friendly-scanner
Call-ID: 257939888571853077765854
Contact: None
Accept: application/sdp
Content-Length: 0

-- end of packet.

I changed our FreePBX IP in the above log to xxx.xxx.xxx.xxx.


Notwithstanding their stated intent to be ‘friendly’, this is a bot scanning for vulnerabilities by attempting to REGISTER to your PBX.

And PJSIP blocked it almost immediately because they’ve violated the SIP specification, and the REGISTER request is invalid.

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@lgaetz + @jcolp - So it is not something I should worry about, or is there some action I should take?

Adjust your hardware and/or FreePBX firewall to deny access to port 5060, except from authorized endpoints and trunks.

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