Every day millions of people go online to find information, to do business, to have a good time. Alas, some people go there to commit crimes as well. Though crimes have been committed via the Internet almost from its very launch, now cybercriminals have become dangerous as never before.

We've been warned lots of times about stealing data -- identity theft, phishing scams and pharming; we have at least heard of denial-of-service attacks and "zombie" computers, and now one more type of online attack has emerged: holding data for ransom. Extortionists remotely encrypt somebody's files and then demand money for the key to decode the information.

Experts say it is not yet a tendency; websites that used to infect users with the Trojan, have been put down. Besides, this program, Trojan.Pgpcoder, exploits a vulnerability in Microsoft Internet Explorer, which users should have patched as long ago as last July. However, there is no guarantee that such attacks won't appear in future, and all PCs will be patched at that time.

Websense, the San Diego-based Web security company, was the first to report such a case two weeks ago, when its customer fell victim to the attack.

Researchers at Symantec also have seen the malicious program used in the ransom attack. Oliver Friedrichs, a senior manager at Symantec Security Response said that attackers could use a website, email, or other means to distribute the Trojan.Pgpcoder and launch a widespread extortion campaign.

When the user visits a malicious website, his unpatched PC gets infected with a Trojan Horse (downloader-aag). This Trojan Horse downloader connects to another website, downloads the encoding application, and runs it.

The malicious encoding program searches for 15 common file types, including images and Microsoft Office files on the computer and encrypts them, and deletes the original files.

Then it creates a file with a ransom note called Attention!!!, where demands $200 for a tool needed to decrypt the files.

However, there is a weak spot in the attackers' scheme. It is possible to trace the money and to catch the extortionists when they try to collect the ransom. Maybe, it will prevent this kind of cybercrime from spreading.

Time will show whether we see this Trojan attack again or something similar appears and there will be a real need for a name for such type of Trojans -- how do you like "ransomware"? I have already seen this word used, but let's hope for the best.

Anyway, it is always wise of users to keep anti-virus and security software up-to-date and back up data. Just to be on the safe side.