Hackers are increasingly relying on so-called "bot networks" to attack core parts of the Internet, send spam, and steal identities, security experts say. Last week, a distributed denial-of-service attack was launched against the systems of Internet advertising company DoubleClick Inc.
That company confirmed in a statement that the attack against its domain name system infrastructure caused severe service disruption for many of its ad-serving customers. Attackers also attempted to launch a similar attack against Microsoft last week but weren't successful.
"It's a result of the dramatic spread of bot networks," says Lloyd Taylor, VP of technology and operations for Internet performance-monitoring company Keynote Systems Inc. Bot networks consist of up to hundreds of thousands of computers on which hackers have placed apps called bots or zombies that can be commandeered to attack any system or network connected to the Internet. Security software vendor Symantec Corp. says it's tracking a half-million systems with bots on them.
Net virus posing as Berg video
A virus purporting to show video of Nick Berg alive has been released on the internet, warn security experts.
The virus is in a message post to tens of thousands of newsgroups, said anti-virus firm Sophos. It is the same one that posed as a suicide note from Arnold Schwarzenegger and as images claiming to show that Osama Bin Laden had killed himself.
Computer owners are advised to ensure their anti-virus software is up-to-date and avoid opening unknown messages. The message is the latest by a group called the Hackarmy designed to spread malicious code which can allow hackers to take control of a computer.