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The World’s Top Spam Sources

By Ken Simpson | 4 minute read

I popped open Excel and generated some stats porn for everyone today.

A graph showing the world's top spam sources, ranked by their position on the CBL blacklist

One of the interesting things we track here at MailChannels is the positioning of the world’s worst spam sources on the world’s best blocklists. The chart above shows the number of blocklist entries on the Composite Blocking List (CBL – link) for each of the top-15 spam sending networks on the Internet. The CBL tracks botnet infections (excellent statistics are available on the CBL web site) by analyzing spam traffic aimed at its extensive honeypot network, and then lists the IP addresses from which this spam traffic originates. The listings are automated, and listings can be easily removed by ISPs through a web page once the bot problem has been resolved. Listings that are not manually removed in this manner do eventually time out on their own.

I suppose one of the interesting things about this chart is that despite the fact that spam almost disappeared over the holidays (see our previous post), the number of CBL listings produced by each of these networks stayed relatively constant during that time period (our chart starts roughly in late November 2010). I’m impressed by the apparent efforts of the folks at (Vietnam Post and Telegraph Company) to clean up their act, resulting in a substantial drop in listings during the time period under analysis. But for most of these providers, it seems that business as usual continues to prevail when it comes to removing bot infections from their networks.

USA vs. Russia vs. Thailand vs. China

The largest spam sources don’t always come from the largest countries. For a variety of reasons, the United States (population 308,745,538) has far fewer bot infections listed in the CBL’s top-100 spamming networks list than the much smaller country of Thailand (population 65,998,436). Russia tops this comparison, however, with nearly 10-times the number of CBL listings in the top-100 spamming networks list during the time period under analysis.

The Worst Spamming Countries

In economic news, we often hear of the “BRIC”, which refers to Brazil, Russia, India, and China. The BRIC nations are fast-growing, with large, young populations, and apparently are also a great source of spam. If we look at the number of spamming networks from each country that are listed in the CBL’s top-100 spamming networks list, we find Russia on top, with India in second place, Brazil in third trailing not far behind, and .. actually, China doesn’t even make the list. China would be on the list weren’t it for the fact that Internet access in that country is highly concentrated among a small group of massive ISPs.

Again, I find it strange that Thailand makes this list, considering its very small population. Armenia is also a surprise – with a population just over 3M, you have to wonder how they manage to get so many networks into the top-100 list of spam sources.


It’s not news (at least, not to me) that the world’s largest spam sources are developing nations. Developing countries are often many years behind developed countries in their acquisition of technology because vendors tend to visit these countries last after developing what is perceived to be more profitable first-world markets initially. We humbly assert that MailChannels is doing its part in the developing world to reduce the spam problem (read our recent case study on outbound spam control at Cambodia’s Ezecom for reference). As we succeed in landing more outbound spam control customers in these markets, my great hope is that the CBL list of 2011 looks a lot better in all respects than it did at the tail end of 2010.

Get your customer emails off of blacklists.