http://tech.nytimes.com/aponline/tec...t-Ransom.html?



The latest threat to computer users doesn't destroy data or steal
passwords -- it locks up a person's electronic documents, effectively
holding them hostage, and demands $200 over the Internet to get them back.

Security researchers at San Diego-based Websense Inc. uncovered the
unusual extortion plot when a corporate customer they would not identify
fell victim to the infection, which encrypted files that included
documents, photographs and spreadsheets.

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A ransom note left behind included an e-mail address, and the attacker
using the address later demanded $200 for the digital keys to unlock the
files.

''This is equivalent to someone coming into your home, putting your
valuables in a safe and not telling you the combination,'' said Oliver
Friedrichs, a security manager for Symantec Corp. The company said
Tuesday the problem was serious but not deemed a high-level threat
because there were no indications it was widespread.

The FBI said the scheme was unlike other Internet extortion crimes.
Leading security and antivirus firms this week were updating protective
software for companies and consumers to guard against this type of
attack, which experts dubbed ''ransom-ware.''

''This seems fully malicious,'' said Joe Stewart, a researcher at
Chicago-based Lurhq Corp. who studied the attack software. Stewart
managed to unlock the infected computer files without paying the
extortion, but he worries that improved versions might be more difficult
to overcome. Internet attacks commonly become more effective as they
evolve over time and hackers learn to avoid the mistakes of earlier
infections.

''You would have to pay the guy, or law enforcement would have to get
his key to unencrypt the files,'' Stewart said.

The latest danger adds to the risks facing beleaguered Internet users,
who must increasingly deal with categories of threats that include
spyware, viruses, worms, phishing e-mail fraud and denial of service
attacks.

In the recent case, computer users could be infected by viewing a
vandalized Web site with vulnerable Internet browser software. The
infection locked up at least 15 types of data files and left behind a
note with instructions to send e-mail to a particular address to
purchase unlocking keys. In an e-mail reply, the hacker demanded $200 be
wired to an Internet banking account. ''I send programm to your email,''
the hacker wrote.

There was no reply to e-mails sent to that address Monday by The
Associated Press.

Ed Stroz, a former FBI agent who now investigates computer crimes for
corporations, said the relatively cheap ransom demand -- only $200 --
probably was deliberately low to encourage victims to pay rather than
call police and to discourage law enforcement from assigning these cases
a high priority.

''That's a very powerful threat,'' Stroz said. ''If somebody encrypted
your files, you need this stuff now to do your work.''

FBI spokesman Paul Bresson said more familiar Internet extortion schemes
involve hackers demanding tens of thousands of dollars and threatening
to attack commercial Web sites, interfering with sales or stealing
customer data.

Experts said the Web site where the infection originally spread had
already been shut down. They also said the hacker's demand for payment
might be his weakness, since bank transactions can be traced easily.

''The problem is getting away with it -- you've got to send the money
somewhere,'' Stewart said. ''If it involves some sort of monetary
transaction, it's far easier to trace than an e-mail account.''