The demise late last year of four of the world's biggest spam botnets was good news for anyone with an email inbox, as spam levels were cut in half - almost overnight. But the vacuum has created opportunities for a new breed of bots, some of which could be much tougher to bring down, several security experts are warning.
New botnets with names like Waledac and Xarvester are filling the void left by the dismantling of Storm and the impairment of Bobax, Rustock, and Srizbi, these researchers say. The new breed of botnets - massive networks of infected Windows machines that spammers use to blast out billions of junk messages - sport some new designs that may make them more immune to current take-down tactics.
Waledac is a good example. It appears to be a complete revision of Storm, that includes the same state-of-the-art peer-to-peer technology and fast-flux hosting found in its predecessor, according to researcher Joe Stewart of Atlanta-based security provider SecureWorks. But it differs from Storm in one significant way: Weak encryption protocols, which proved to be an Achilles Heel that led to its downfall, have been completely revamped.