At least 100,000 computers in the U.K. are infected with the Zeus malware, an advanced piece of spying software that is regularly defeating most antivirus software suites, according security vendor Trusteer.

Researchers at Trusteer managed to analyze a server used to collect details from the hacked PCs, which likely became infected by visiting Web sites engineered to attack computers and install Zeus, said Mickey Boodaei, Trusteer's CEO.