Archive for May, 2016

AcmePacket: go on rejecting!

Thursday, May 19th, 2016

One more post about INVITE rejecting.

The task: reject malicious SIP traffic coming from some country to our number. All INVITEs contain a From: header with 12-digits number starting with 666. The may also contain a plus sign at the beginning or 810, or +810.

It is also important to set a ‘new-value’ parameter, containing a status code and SIP description (in form of “Code:Description”), as some (or maybe most) PBXses/softswitches/proxies go on sending INVITEs if we just do ‘action reject’. After answering from AcmePacket with something like “403 Forbidden” the remote side stops sending endless INVITEs to AcmePacket.


Part of sip-manipulation:

                name                                    dropHACKERS
                header-name                             From
                action                                  manipulate
                comparison-type                         pattern-rule
                msg-type                                any
                methods                                 INVITE
                        name                                    dropHACKERS1
                        parameter-name                          From
                        type                                    uri-phone-number-only
                        action                                  reject
                        match-val-type                          any
                        comparison-type                         pattern-rule
                        match-value                             666[0-9]{9}$
                        new-value                               403:Forbidden

This is how it looks like after rejecting malicious INVITE with “403 Forbidden”: