LINDON — The SCO Group Inc., the target of hatred by some supporters of the Linux computer operating system, on Tuesday offered a $250,000 reward for the arrest and conviction of whoever created the "Mydoom" worm that created occasional havoc at the company's Web site and caused e-mail troubles worldwide.

The company confirmed Tuesday that it had been hit by a "distributed denial-of-service" attack — when a Web site locks up because it cannot keep up with a flood of inquiries or e-mails — from Mydoom. However, the site appeared to have been available most of Tuesday, SCO spokesman Blake Stowell said.

Lindon-based SCO, which has suffered at least three other service-denial attacks, offered the reward of up to $250,000 for information leading to an arrest and conviction of the Mydoom troublemakers.

"During the past 10 months, SCO has been the target of several DDOS attacks," Darl McBride, SCO president and chief executive officer, said in a prepared statement. "This one is different and much more troubling, since it harms not just our company, but also damages the systems and productivity of a large number of other companies and organizations around the world. The perpetrator of this virus is attacking SCO, but hurting many others at the same time."

SCO has drawn the wrath of supporters of Linux, a so-called "open-source" operating system consisting of contributions from developers worldwide, by claiming that SCO Unix operating system code has been misappropriated by several companies and placed into Linux. SCO has sued International Business Machines Corp. and Provo-based Novell Inc. and been sued by Linux distributor Red Hat over Linux-related issues.

SCO has offered licenses to Linux users as a way of avoiding litigation, leaving many Linux boosters to say SCO is trying to get rich through litigation or threats of litigation rather than through regular business operations.

"We do not know the origins or reasons for this attack, although we have our suspicions," McBride said Tuesday. "This is criminal activity, and it must be stopped."

SCO said it is working with U.S. law enforcement authorities, including the U.S. Secret Service and Federal Bureau of Investigation, to determine who caused the problems.

Computer security company Symantec Corp. said Tuesday it found code in the wide-sweeping virus that would flood the SCO Web site with requests in an attempt to crash its server starting Sunday. The program is slowing companies' e-mail systems by installing a command in infected computers to send a flood of requests for information to the SCO site, according to F-Secure and Symantec.