"A computer worm that China warned Internet users against is an updated version of the Panda Burning Incense virus, which infected millions of PCs in the country three years ago, according to McAfee. The original Panda worm, also known as Fujacks, caused widespread damage at a time when public knowledge about online security was low, and led to the country’s first arrests for virus writing in 2007. The new worm variant, one of many that have appeared since late 2006, adds a malicious component meant to make infection harder to detect, said Vu Nguyen, a McAfee Labs researcher.
"It has gotten more complex with the addition of a rootkit," said Nguyen. "It definitely makes it more challenging for users to clean up and even to know that their systems have been compromised." A rootkit burrows into a system to try to hide the existence of malware." – Content courtesy of China warns of mass Internet virus – Techworld.com