Comment 3 for bug 94792

This looks right:

http://svn.digium.com/view/asterisk/branches/1.2/channels/chan_sip.c?r1=56230&r2=57475

If a SIP message comes in and goes to a method handler that requires additional values that may not be present then send back an error.

Compare http://voipsa.org/pipermail/voipsec_voipsa.org/2007-March/002275.html (also the date).

I will run an exploit against my Asterisk if one available to verify that this patch fixes the problem.