Emulating SIP with HoneyPoint

Last week, Hos and I worked on identifying how to emulate a SIP endpoint with HoneyPoint Security Server. We identified an easy way to do it using the BasicTCP capability. This emulation component emulates a basic TCP service and performs in the following manner:

  • Listens for connections
  • Upon connection, logs the connection details
  • Sends the banner file and awaits a response
  • Upon response, logs the response data
  • Sends the response, repeating the wait and log loop, resending the response to every request
  • When the connection limit is reached, it closes the connection
It has two associated files for the emulation:
  • The banner file – “banner”
  • The response file – “response”

In our testing, we were able to closely emulate a SIP connection by creating a banner file that was blank or contained only a CR/LF. Then we added the appropriate SIP messaging into the response file. This emulates a service where thew connection is completed and logged, and the system appears to wait on input. Once input is received, then a SIP message is delivered to the client. In our testing, the SIP tools we worked with accepted the emulation as SIP server and did not flag any anomalies.

I’ll leave the actual SIP messaging as a research project for the reader, to preserve some anonymity for HPSS users. But, if you are an HPSS user and would like to do this, contact support and we will provide you with the specific messaging that we used in our testing.

As always, thanks for reading and especially thanks for being interested in HoneyPoint. We are prepping the next release, and I think you will be blown away by some of the new features and the updates to the documentation. We have been hard at work on this for a while, and I can’t wait to share it with you shortly!

Just a Reminder, SIP is a Popular Scanning Target

I just wanted to give you a quick reminder that SIP scanning remains quite popular on the Internet. These probes can lead to compromise and fraud against your VoIP systems. Make sure you do not have VoIP systems exposed to the Internet without proper controls. If you review your logs on the Internet perimeter, SIP scans will look similar to this:

This was captured from the HITME using HoneyPoint Personal Edition.

2013-09-30 17:02:18 – HoneyPoint received a probe from on port 23

Input: OPTIONS sip:nm SIP/2.0

Via: SIP/2.0/TCP nm;branch=foo

From: <sip:nm@nm>;tag=root

To: <sip:nm2@nm2>

Call-ID: 50000


Max-Forwards: 70

Content-Length: 0

Contact: <sip:nm@nm>

Accept: application/sdp

Keep an inventory of your VoIP exposures. They remain a high area of interest for attackers.