One of the worlds stealthiest pieces of malware infected more than 4.5 million PCs in just three months, making it possible for its authors to force keyloggers, adware, and other malicious programs on the compromised machines at any time.The TDSS rootkit burst on the scene in 2008 and quickly earned the begrudging respect of security experts for its long list of highly advanced features. It is virtually undetectable by antivirus software, and its use of low-level instructions makes it extremely hard for researchers to conduct reconnaissance on it. A built-in encryption scheme prevents network monitoring tools from intercepting communications sent between control servers and infected machines……..

via Indestructible rootkit enslaves 4.5m PCs in 3 months • The Register.