Change \w+ to .* to account for domains with hyphens.

ubuntu/resources/fail2ban/sip-auth-failure.conf

@@ -12,7 +12,7 @@
 #          (?:::f{4,6}:)?(?P<host>[\w\-.^_]+)
 # Values:  TEXT
 #
-failregex = \[WARNING\] sofia_reg.c:\d+ SIP auth failure \(REGISTER\) on sofia profile \'\w+\' for \[.*\] from ip <HOST>
+failregex = \[WARNING\] sofia_reg.c:\d+ SIP auth failure \(REGISTER\) on sofia profile \'.*\' for \[.*\] from ip <HOST>
 
 # Option:  ignoreregex
 # Notes.:  regex to ignore. If this regex matches, the line is ignored.