Discovered by Czech researchers, the botnet has been spreading by taking advantage of poorly configured routers and DSL modems, according to Jan Vykopal, the head of the network security department with Masaryk University's Institute of Computer Science in Brno, Czech Republic.

The malware got the Chuck Norris moniker from a programmer's Italian comment in its source code: "in nome di Chuck Norris," which means "in the name of Chuck Norris." Norris is a U.S. actor best known for his martial arts films such as "The Way of the Dragon" and "Missing in Action."

Security experts say that various types of botnets have infected millions of computers worldwide to date, but Chuck Norris is unusual in that it infects DSL modems and routers rather than PCs.

It installs itself on routers and modems by guessing default administrative passwords and taking advantage of the fact that many devices are configured to allow remote access. It also exploits a known vulnerability in D-Link Systems devices, Vykopal said in an e-mail interview.

A D-Link spokesman said he was not aware of the botnet, and the company did not immediately have any comment on the issue.