The proportion of spam in e-mail traffic continued its gradual decline in June, falling a further two percentage points compared to May and averaging 71,9% for the month.

At the same time, new techniques were deployed that made use of spam to infect users’ computers, according to Kaspersky Lab.

The start of the European holiday season, for instance, was marked by the launch of a mass mailing of fake hotel reservation notifications that were accompanied by a malicious attachment. To avoid falling victim to this sort of scam users should be particularly careful when booking trips online and remember that no respectable tour firm will send reservation confirmations as a zipped archive.

Not so long ago spammers were making active use of a social engineering trick that involved the sending of malicious code in an e-mail attachment that supposedly contained a photo of a girl who wanted to befriend the recipient. June saw a new version of this photographic theme whereby the recipient was threatened with legal action for posting photos online without the owner’s consent. The photos in question were supposedly attached to the e-mail in the form of a zipped archive. Yet another photo-related trick this month was that of fake notifications about fines for traffic violations. The archive attached to the message is passed off as the set of incriminating photos taken by surveillance cameras, but which actually contained a malicious programme.

Perhaps the most popular event of the month was the European Football Championship which lasted the whole of June. The spammers couldn’t resist exploiting all the interest it generated and even started spreading Euro 2012-related mass mailings at the beginning of the year. In addition to the earlier offers to buy tickets for fan zones showing matches live on big screens and offers to rent apartments in the host cities, June saw the arrival of spam advertising football sites dedicated to the tournament.

Meanwhile, on 4  July, the US celebrated one of its main national holidays – Independence Day. As is the case with any other major holiday in the western hemisphere it was accompanied by a wave of spam offering fake designer watches and various other accessories as gift ideas. There were also mass mailings advertising flags to help Americans express their patriotic feelings.

The share of all spam received by European users that originated in China increased by almost 50% compared to the previous month. The UK was the only European country in May’s rating that didn’t make it into June’s Top 20. Among the leading distributors of spam in the European region were two other European countries – Italy (1.5%) and Germany (0.91%). More than half of all the spam distributed in Europe still came from Asia.

Once again, the Top 20 rating of countries that distributed spam on the territory of the US in June was topped by the US itself. For the second month in a row over one third of all US spam was ‘homemade’, with an increase of five percentage points compared with the previous month. A quarter of the spam distributed on US territory is of Asian origin.

“The proportion of spam in total mail traffic continued to fall for the second month in a row. A drop of two to three percentage points may not sound very much, however it could signal some major changes are taking place,” says Maria Namestnikova, senior spam analyst at Kaspersky Lab. “Summer is a quiet season in terms of business activity, when the amount of spam falls together with the overall volume of e-mail traffic. That’s why only a significant decrease in the volume of unsolicited e-mails will lead to such a noticeable drop in the proportion of spam in overall mail traffic.”