Police in Kyoto, Japan, have arrested three men who are said to have been involved in a plot to infect users of the P2P file-sharing network Winny with a Trojan horse that displayed images of popular anime characters while wiping music and movie files. The malware, which has been dubbed Harada in media reports, is believed to be related to the Pirlames Trojan horse which was intercepted in Japan last year.

According to Japanese media reports, the three men have admitted their involvement in the crime. Masato Nakatsuji, a 24-year-old student, is said to have written the malware, while 39-year-old Shoji Sakai and Katsuhisha Ikema, 35, are said to have distributed the malicious code via Winny.

"Normally you would expect malware writers to be arrested for breaking into computers with their code or damaging data, but in this case he is accused of breaching copyright because he used cartoon graphics without permission in his Trojan horse. Because this is the first arrest in Japan of a virus writer it's likely to generate a lot of attention and there will be many people watching to see the outcome," said Graham Cluley, senior technology consultant for Sophos. "Malware is truly a global menace, impacting on every user of the Internet, and it is good to see police around the world doing their bit to tackle the problem."

Isamu Kaneko, the author of the Winny file-sharing program, was fined by a Japanese court in December 2006 for assisting in copyright violation. The rights and wrongs of the case have been widely debated on the Internet.

A survey conducted in 2006 by Sophos reflected the serious concern that uncontrolled applications are causing system administrators. For example, 86.5 percent of respondents said they want the opportunity to block P2P applications, with 79 percent indicating that blocking is essential.

"Businesses are increasingly looking to control users' access to P2P file-sharing software not just because they can eat up bandwidth or infringe copyright laws, but also because they can present a security risk to your corporate data," continued Cluley. "This music and movie-munching Trojan horse is a timely reminder of the danger malware can pose to a company's network."