It's the early 21st Century, the United States is the reigning capital of computer attacks, hackers have become international crime rings, and you can buy a stolen credit card number for as little as $1 or a complete identity for $14.

This might read like near-future science fiction, but it's reality, according to a new security report released Monday by Symantec, covering the last six months of 2006.

The Internet Security Threat Report, issued twice yearly by the computer security firm, paints a grim picture. "Attackers are now refining their methods and consolidating their assets to create global networks that support coordinated criminal activity," the report stated.

While a recent report from McAfee showed that Internet domains from Romania, Russia, and the tiny island of Tokelau were among the riskiest in relative terms, the Symantec report found that the U.S. is the source of about 31 percent of all malicious computer activity, beating China (7 percent) and Germany (7 percent).

As for servers used for buying or selling stolen personal information, 51 percent were located in the U.S.

In most areas profiled in the report, the situation has gotten worse. Nearly 30 percent more computers are part of botnets than the previous six months. Trojans can take over a computer without the user knowing it, turning it into a zombie machine used for pumping out spam, launching denial-of-service attacks, or participating in other nefarious activities at the behest of the remote hackers.

On a given day in the period the report covered, there were an average of about 64,000 active bot computers, with China having the highest number.

If you thought you're seeing more and more junk mail, you're right. Spam makes up an astounding 59 percent of all email traffic, the report said, an increase of 5 percent over the first half of the year.