Facebook and other Web sites such as MySpace, Bebo and Google are creating technology platforms that let third-party developers build applications to run on those sites. The concept has opened the door to innovation, but also prompted worries over how those applications could be used for spam or to steal personal data.

The demonstration of a vulnerability in the Border Gateway Protocol is only the latest attack to highlight fundamental security weaknesses in some of the internet’s core protocols. Those protocols were largely developed in the 1970s with the assumption that every node on the then-nascent network would be trustworthy.