The so-called Reveton ransomware virus can attack a computer immediately when a user clicks on a contaminated Web site, the Los Angeles Times reported Saturday. The virus then holds the computer for ransom, keeping operations locked up while flashing messages that say the owner of the computer has broken the law and charges will be filed if the user does not forward money through a money card system.
Some of the messages fraudulently claim they are from a law enforcement agency, such as the Department of Justice or the FBI. Some of the messages claim the computer's Internet address can be tracked from Web sites that broadcast child pornography.
Authorities said affected computers should be checked out by a professional who can remove the virus.
Even if a user can figure out how to unlock a computer, the system could still be infected with the virus, officials said.