The Federal Trade Commission has launched an international effort to crack down on the use of zombie computers by spammers.
Dubbed "Operation Spam Zombies," the campaign aims to educate ISPs and others about zombie computers - systems hijacked via hidden software - that are used by spammers to route junk emails and hide their origin.
Twenty members of the London Action Plan, an international anti-spam group, and 16 government agencies plan to send letters to more than 3,000 IPS worldwide, urging them to implement tactics to defeat spam zombies, according to the FTC.
Suggested methods include blocking a common port used for email; applying rate-limiting controls for email relays; identifying computers that are sending abnormal amounts of email and possibly quarantining them; and providing customers with tools to remove malicious code that hijacked their computers.
The FTC said the next phase of the operation likely will involve identifying spam zombies and urging the network operators hosting them to take action.
Government agencies from more than 20 countries have joined the FTC effort, including Argentina, Australia, and Taiwan.
Researchers at antivirus supplier Sophos estimated that 50 percent of all spam orginated from zombie computers.
Gregg Mastoras, senior security analyst at Sophos, applauded the FTC campaign, but added that efforts to stop internet criminals should not infringe on consumers' privacy and free speech.
"While ISPs need to be responsible for identifying suspect computers through unusual patterns - though not necessarily content - and taking action when needed, consumers need to be equally responsible for safe computing," he said in a statement.
Earlier this month, SC Magazine reported that zombie computers are fast becoming the weapon of choice for organized gangs to launch phishing attacks.