WASHINGTON: The US effort to curb the flood of unwanted e-mail or “spam” has lost momentum, a survey showed on Monday, leaving the United States at the top of the heap for this scourge of the Internet.

A quarterly survey by the Internet security firm Sophos found the US leading the world as the source of 23.2 per cent of all spam e-mails delivered globally.

Most of the spam delivered around the world is relayed though “zombie” personal computers infected by viruses that automatically spread the unwanted email, often without the knowledge of the PC owners. And Sophos said “vast zombie networks” are often controlled by Russian spammers.

But Sophos said US progress in halting spam since the passage of a 2003 law dubbed CAN-SPAM appears to have stalled.

“It’s disappointing to see the United States lose some of its momentum in the war against spam; US spam has declined every quarter since the inception of CAN-SPAM until now. Despite the increase in arrests and significant monetary penalties, it’s clear that the United States has more work to do,” said Ron O’Brien, senior security analyst for Sophos.

“With a concerted focus on regulatory action and judicial punishment, the United States must now intensify its efforts to educate computer users on preventive security measures to curb the infestation of zombie computers.”—AFP