Skype: user IP address disclosure

The guys over at skype-open-source found this interesting “howto” on pastebin regarding how to obtain the IP address (both public and internal IPs) of every Skype user: it even works if the “victim” is not on the “attacker” contact list, and vice-versa.
Here is the relevant info:

  1. Downloading this patched version of Skype 5.5: http://skype-open-source.blogspot.com/2012/03/skype55-deobfuscated-released.html
  2. Turn on debug-log file creation via adding a few registry keys: https://github.com/skypeopensource/skypeopensource/wiki/skype-3.x-4.x-5.x-enable-logging
  3. Make "add a Skype contact" action, but not send add request, just click on user, to view his vcard(general info about user). This will be enough.
  4. Take look in the log of the desired skypename.
  5. The record will be like this for real user ip: -r195.100.213.25:31101
  6. And like this for user internal network card ip: -l172.10.5.17

The original post is here Skype user IP-address disclosure – Pastebin.com.