Trend Micro Inc., a Japanese maker of antivirus software, said part of its Web site was hacked into, allowing a virus to be downloaded onto computers of people viewing the page.
The company issued an apology Wednesday on its Web site, saying it resolved the problem that day. The change to one of its virus information pages was made on March 9 around 9 p.m. and remained until around 11:30 a.m. Wednesday, the company said.
Trend Micro hasn't confirmed the source of the hacking, spokesman Daisuke Uchida said. The virus works by downloading other viruses from the Internet, he said.
Users who are concerned their computer may be infected can use the company's freely available online antivirus software to purge the program, Trend Micro said.