The United States is by far the leading originator of most of the spam received around the world, according to a study published on Thursday by UK antivirus company Sophos.
The broad international spread of junk email senders, with European and Asian countries also high on the list, underscores the difficulty of combating spam with national laws, Sophos said. An added difficulty is that many spam senders may not even be aware they are sending the messages, their PCs having been hijacked by the real culprits from across international borders.
The US accounted for more than half of all spam received, at 56.74 percent, Sophos said, with Canada a distant second place at 6.8 percent. The top-ranked European country was the Netherlands at 2.13 percent, while the UK scored ninth with 1.31 percent. The top-ranked European spammers -- the Netherlands, Germany, France, the UK and Spain -- together accounted for 7.82 percent of all spam received.
"Spam is a global problem, and countries worldwide are starting to take the issue more seriously," said Sophos senior technology consultant Graham Cluley in a statement. "However, legislation in the UK won't protect users from spam coming from North America or China."
Sophos arrived at the figures by analysing hundreds of thousands of emails received over two days last week in various locations around the globe.
The analysis only scratches the surface of understanding the spam problem, Cluley said, noting that about a third of all spam is sent from computers that have been compromised by junk emailers, often without the knowledge of the computer owner.
Sophos said that many of the US computers originating spam appear to be controlled by hackers in Russia and elsewhere.