The availability of a patch for a security flaw doesn't always solve the problem, according to a new study published today.

According to the new Security Labs Report from M86 Security, the top six most frequently observed vulnerabilities on the Web were all discovered at least four years ago, and have all been patched for at least two years.

Most of the top 15 flaws detected by M86 Security were on Windows or Adobe applications, and most have been around for some time -- MS Office Web Components active script execution, for example, has been known since 2002, yet it is still No. 2 on the most frequently detected list.

"Despite the fact that these vulnerabilities were patched years ago, many of them are still targeted today," the report says. "This is likely a result of their success rates, and it reinforces the importance of updating software applications, from browsers to PDF readers."

The report also lists the top 10 exploit kits, where Eleonore remains the most popular and Phoenix comes in at No. 2.

"Based on our data, we concluded that the popularity of an exploit toolkit is based on the same factors as most software applications," the report says. "There is a direct correlation between the toolkit’s popularity and the number of releases throughout the year and support available to toolkit customers. The media exposure for each toolkit and pricing also contribute to its popularity. Some kits sell for as low as $150, while others, such as the Phoenix exploit kit, can be purchased for $2,000."

The report, which covers activity in the second half of 2010, showed a marked drop-off in spam, but spam still makes up the vast majority of all email traffic. Rustock, a well-known botnet, carried more than half of all spam traffic during that time period, according to the report.

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