Security experts have upgraded the threat level of a fast-spreading worm that could potentially wipe out files on a hard drive or make a computer crash.
The computer worm, W32.Sir Cam or Sir Cam, which arrives with an email attachment, asks victims in either Spanish or English to open an attached document.
The virus, which sends copies of itself to all email addresses in the computer's Microsoft Outlook address book, was discovered early last week and now appears to have sharply escalated.
Symantec's AntiVirus Research Center (SARC) classified the worm as a "severe" threat. According to SARC, several hundred computers at a handful of sites have been infected with the worm.
SARC reported that the worm arrives as an email message with the following content: the subject of the email will be random and will be the same as the filename of the attachment in the email.
The message body will be semi-random but will always contain one of the following two lines, in English or in Spanish, as the first and last sentences of the message:
The first line will read "Hi! How are you?" Or "Hola, como estas?"
And the last line will read: "See you later. Thanks and Nos vemos pronto, gracias."
Many anti-virus vendors, including Trend Micro and McAfee, also issued updates to defend against Sir Cam. The virus is now No. 1 on Trend Micro's live tracking map of the Top 10 threats.
The general agreement among security and antiviral firms now is that Sir Cam is both a virus and a worm as it performs malicious actions on a computer similar to a virus, yet also replicates itself as a worm does.
When activated, the virus randomly chooses whether to take over all the unused space on a hard drive by filling it with text, or whether to delete the contents of the hard drive.
Sir Cam also worms its way into an infected computer's operating system and changes its identity with every infected email it sends.
Comcast's £29.7bn winning bid more than twice the £13.7bn Rupert Murdoch valued Sky at just eight years ago
A nuclear strike has been considered, but Bruce Willis is nowhere in sight
Spray-on antenna could enable seamless integration of antennas with everyday objects
Parker Solar Probe, TESS and GOLD missions will deliver exciting data, claims NASA