Internet Attacks Hit Spam Blockers

Three Web sites that provide spam blocking lists have shut down as a result of crippling Internet attacks in what experts Thursday said was an escalation in the war between spammers and opponents of unsolicited e-mails.

Anti-spam experts said they thought spammers were behind the attacks, although they had no way of proving it.

The technological war comes as Congress considers a federal anti-spam law and California adopts what is widely considered to be the toughest law in the country.

The California law, signed Tuesday, allows people to sue spammers for $1,000 per unsolicited e-mail and for as much as $1 million for a spam campaign.

“This definitely marks an escalation in the spam wars,” Andrew Barrett, executive director of the Spamcon Foundation, a spam watchdog group, said of the recent Internet attacks.

“Before, it was a guerrilla war.... This is the first time we’ve seen [spammers] employ such brazen tactics,” he said.

Anti-spam advocates maintain hundreds of spam block or “black hole” lists, which are Web sites with lists of the numerical Internet protocol addresses of specific computers or e-mail servers that are unsecure or are known sources of spam.

Network administrators and Internet service providers consult the lists and block e-mails coming from those computers as part of their spam filtering techniques.

Two of those spam block lists have shut down after being hit by denial-of-service attacks, in which compromised computers are used to send so much traffic to a Web site that it is temporarily taken down. The operator of another list shut down fearing a pending attack.

“There seems to be a methodical, well-planned attempt to use pre-assembled networks of zombie machines to create sustained denial-of-service attacks on servers where these block lists run,” Barrett said.

Monkeys.com shut down on Monday after a three-day denial-of-service attack over the weekend and an attack last month that lasted 10 days, list operator Ronald Guilmette said in a posting to an anti-spam news group.

“The handwriting is now on the wall,” he wrote. “I will simply not be allowed to continue fighting spam.”

Spam block list operator Osiriusoft.com also recently shut its list after a denial-of-service attack, and on Tuesday the list maintained at Tennessee Internet service provider Compu-Net Enterprises was taken down.