Sophos, a world leader in integrated threat management, has published its latest report on the top 12 spamming countries during the last six months.

Experts at SophosLabs analyzed all spam messages received in its global network of spam traps to identify the top 12 countries of origin for spam. The United States remains the worst offender, but is relaying significantly less of the world's spam than it did a year ago, while spam traffic from China and South Korea increased substantially.

Meanwhile, Sophos found that more than 60% of spam is now generated from zombie computers -- hijacked PCs infected by malware. The evolving nature of spamming now allows culprits to be in a different country than the innocent computers they exploit.

The "Dirty Dozen" countries are as follows (figures in brackets denote percentages for the same period in 2004):

April - September 2005

1. United States 26.35% (41.50%)
2. S Korea 19.73% (11.63%)
3. China (incl. Hong Kong) 15.70% (8.90%)
4. France 3.46% (1.27%)
5. Brazil 2.67% (3.91%)
6. Canada 2.53% (7.06%)
7. Taiwan 2.22% (0.86%)
8. Spain 2.21% (1.04%)
9. Japan 2.02% (2.66%)
10. United Kingdom 1.55% (1.07%)
11. Pakistan 1.42% New Entry
12. Germany 1.26% (1.02%)

Others: 18.88% (18.10%)

While the United States, South Korea and China still account for more than 50% of all spam, the United States and Canada have significantly reduced their role in the problem. Sophos has seen a sharp drop in spam sent from North American computers due to a number of factors: jail sentences for spammers, tighter legislation, and better system security.