Canadian computers — many of them unwittingly — send out over nine billion spam e-mails a day, almost five per cent of all global spam traffic, according to a report from network and internet security firm Cisco.

In an annual security report released Monday, Cisco estimated almost 200 billion messages per day, or 90 per cent of all e-mails sent worldwide — can be defined as spam, double the volume of the previous year.

E-mail spam is rarely sent from the computers of the spammers themselves, the report said. Instead they use a number of techniques, from phishing scams, to e-mail with attached malware, to hijacking the computers of unwitting people. The spammers then use these networks of computers — called botnets — to send out more spam.

While many spammers still send out mass-mailing spam to millions of untargeted recipients, web security software is usually able to filter these messages, the company said.

Trickier to handle are "phishing" scams designed to elicit personal or financial information that is often smaller, more targeted and harder to spot, the report said.

Botnets are networks of computers that have been hijacked by malicious groups or individuals to do their bidding. Their owners are usually unwitting victims who have no idea their machines have been infected and turned into so-called "zombies" or "bots."

The zombie computers are typically used to distribute spam or phishing e-mails, or viruses and Trojans that are used to hijack other computers. Botnet operators often rent time or bandwidth on their networks to spam e-mail marketers and phishing scam artists.

The United States was the single largest source of outgoing spam messages, Cisco reported, accounting for 17.2 per cent of all global spam.

Canada was the fourth biggest source, with 4.7 per cent of all global spam, behind the U.S., Turkey (9.2 per cent) and Russia (8.0 per cent), and had the highest percentage of spam on a per-capita basis of the 16 top nations.

Canada's privacy commissioner, Jennifer Stoddart, has been pushing for over a year for Canada to enact legislation to fight spam. Canada is the only G8 country without anti-spam legislation, she said when first drawing attention to the issue last year.

The federal Conservative party said in its party platform during the fall election that it would introduce legislation to prohibit the use of spam to collect personal information under false pretences and to engage in criminal conduct, establishing new fines for lawbreakers.

Last month, a California court ordered Montreal resident Adam Guerbuez and his company Atlantis Blue Capital to pay the popular social networking site $873 million US in damages for spamming registered users on the site.

The civil case was filed under the U.S. 2003 anti-spam legislation known as CAN-SPAM (Controlling the Assault of Non-Solicited Pornography and Marketing Act).

Corrections and Clarifications

  • We initially reported that Cisco estimated nearly 900 billion spam messages were sent a day. In fact, the correct number was 200 billion spam messages a day. Dec. 16, 2008|3:13 p.m. ET