[This may open up new markets for "secure platform" computing based on Macintosh OSX and Chrome OS]
A new and improved botnet that has infected more than four million PCs is "practically indestructible," security researchers say.
"TDL-4," the name for both the bot Trojan that infects machines and the ensuing collection of compromised computers, is "the most sophisticated threat today," said Kaspersky Labs researcher Sergey Golovanov in adetailed analysis Monday.
TDL-4's makers use the botnet to plant additional malware on PCs, rent it out to others for that purpose and for distributed denial-of-service (DDoS) attacks, and to conduct spam and phishing campaigns. Kaspersky said TDL-4 has installed nearly 30 different malicious programs on the PCs it controls.