Practical BGP-based hijack/man-in-the-middle attack
One of the presentations at the recent Defcon 16 event demonstrated how you can use the very common laziness of the Internet Service Providers to hijack any prefix you want (just ask YouTube). Nothing new so far, but the part where they fake the AS path in the hijacked announcement to create a safe (hijack-free) conduit back to the destination is brilliant ... and the TTL manipulation is the icing on the cake.
Of course this is a well-known BGP vulnerability (actually, implementation sloppiness on the part of ISPs) that we've been writing about for a long time, but the Defcon presentation is probably the first documented step-by-step recipe for a realistic MITM attack.
Hat tip to Jeremy Stretch; I found the link to the Defcon presentation on his blog.