Unusual CDR entries


i am seeing a growing number of odd CDR entries when I run the standard reports in Freepbx.
2013-10-09 11:55:09 1381316109.103519 DAHDI Overseasnumber Playback s ANSWERED 00:05

The part that confuses me the most id the dest. just showing “s”. Any ideas what this may relate to? (IE is this normal beavhiour). We don’t have any destinations in the system that begin with s, some are from UK numbers sending to our fax number from mobiles (so could just be a misdial).

Other App. sources are receivingFAX, SayAlpha, Hangup and Playback. In one case the entry looks like someone has called in and then tried to log in to one of our phone queues so i am wondering if it’s some kind of hacking attempy over DAHDI channel?

Any guidance on this would be appreciated.


Is your system exposed to the Internet?