Hello bugtraq-list folks.
I recently demonstrated at Athcon, a new security conference taking place
in Athens - Greece, a new stealthy port scanning attack that is made
possible by abusing XMPP. The technique uses a "zombie" host (that can be
anyone in your [most probably fake] friend/contact list) and some timing
calculations in order to conduct a portscan through that proxy to any
target. The IP address is never revealed to the scanned victim, the same
way the famous idle/zombie scan, discovered by antirez, works.
The idea, a proof of concept pidgin patch and a detailed analysis can be
read in the paper.
You can find the whitepaper here:
and the presentation slides:
It is interesting to see how protocols like seemingly "innocent" protocols
like XMPP can still be abused to do things like the above attack.