WormTerminator

The fast spreading worm is becoming one of the most serious threats to today´s networked information systems. A fast spreading worm could infect hundreds of thousands of hosts within a few minutes. In order to stop a fast spreading worm, we need the capability to detect and contain worms automatically in real-time. While signature based worm detection and containment are effective in detecting and containing known worms, they are inherently ineffective against previously unknown worms and polymorphic worms. Existing traffic anomaly pattern based approaches have the potential to detect and/or contain previously unknown and polymorphic worms, but they either impose too much constraint on normal traffic or allow too much infectious worm traffic to go out to the Internet before an unknown or polymorphic worm can be detected. In this paper, we present WormTerminator, which can detect and completely contain, at least in theory, almost all fast spreading worms in real-time while blocking virtually no normal traffic. WormTerminator detects and contains the fast spreading worm based on its denning characteristic - a fast spreading worm will start to infect others as soon as it successfully infects one host. WormTerminator also exploits the observation that a fast spreading worm keeps exploiting the same set of vulnerabilities when infecting new machines. To prove the concept, we have implemented a prototype of WormTerminator and have examined its effectiveness against the real Internet worm Linux/Slapper.