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 a detailed analysis Monday.
"[TDL-4] is practically indestructible," Golovanov said.
"I wouldn't say it's perfectly indestructible, but it is pretty much indestructible," said Joe Stewart, director of malware research at Dell SecureWorks and an internationally-known botnet expert, in an interview today. "It does a very good job of maintaining itself."
Golovanov and Stewart based their judgments on a variety of TDL-4's traits, all which make it an extremely tough character to detect, delete, suppress or eradicate.