McAfee: Spammers Speed Domain Cycling To Stay Off Blacklists

In August, major spam campaigns ran through 72 percent more domains per hour than the month prior, the Santa Clara, Calif. company said.

Spammers often use multiple URLs in their campaigns to avoid anti-spam blacklists, then change the embedded links as each batch of junk mail goes out. The dramatic increase in the number of different domains shows that spammers are stepping up their attempts to stay ahead of security defenses.

"It's a cat and mouse game where spammers try to change their URLs faster than the anti-spam companies can react," said Guy Roberts, McAfee development manager, in a statement. "If it takes traditional blacklists 15 to 20 minutes to block a site, then that's how fast the spammers need to change their URLs.

"Since domains cost only $6 per registration, the spammer is spending less than $100 for four hours of advertising," said Roberts.