A new computer virus is spreading across the Internet, but security experts say that it hasn't resulted in much damage and that its impact is primarily psychological.
The virus, called Conficker or Downadup, first appeared in November but has recently become more prevalent, infecting millions of machines by some estimates.
Technically it's a worm, a kind of malicious software that automatically spreads itself from computer to computer. The cyber-security community is up in arms because worms haven't been an issue for years.
Over the course of the decade, computer hackers shifted their techniques away from rapidly spreading worms — people will remember worms like "Blaster" and "Melissa" that shut down entire offices for a day or two — towards targeted snippets of code that are harder to detect.
The reason: money. Worms are basically a big irritant; code that gets past security software can be used to steal information or make a computer send spam email, both of which command a big price on the black market.
In theory, Conficker could be used for these nefarious purposes, but to date it hasn't been.
"This is serious to the extent that it is a return of a threat that we haven't seen in some time," says Alfred Huger, a security researcher at Symantec.
Michael Argast of the security company Sophos adds that all Conficker is doing now is "causing headaches for IT administrators."