The annual IBM Internet Security Systems (ISS) security trends report published this week shows 7,427 software bugs were catalogued last year, an increase of 39.5% over the number of vulnerabilities identified in 2005.

IBM listed itself among the Top 10 vendors whose products accounted for 964 of the 7,424 disclosed software vulnerabilities. According to the report, the Top 10 vendors for last year, in descending order, are Microsoft, Oracle, Apple, Mozilla, IBM, Linux Kernal Organisation, Sun, Cisco, HP and Adobe Systems.

The report says 86% of the Top 10 vendors’ publicly disclosed vulnerabilities received a software patch.

The remaining balance of the 2006 vulnerabilities are ascribed to “other vendors,” and 65% of these software flaws were patched, according the IBM ISS report.

The 39.5% spike in the number of vulnerabilities can be attributed to the type of tools security experts use now to evaluate software, said Gunter Ollmann, director of the X-Force research and rapid-response division within Internet Security Systems. “The use of fuzzing technology in the automated tools can find where bugs lie,” Ollman said.

Automated fuzzing tools typically run scripts that are tuned to throw garbled data at an application and see how it handles it, revealing many unwanted code-execution risks. These are often catalogued as medium risks, rather than high or low-risk.

In general, the number of vulnerabilities discovered each year has been growing since 2000, and the risks associated with those vulnerabilities have been getting worse. In the year 2000, only 43.6% of vulnerabilities could be remotely exploited, while in 2006, that number reached 88.4%, according to the report.

For one, spam messages have grown in size over the last two years, increasing from an average of 6KB to 9.5KB. “This is largely due to the increased inclusion of random data designed to help spam bypass the first-generation anti-spam technologies, and the use of images to convey message content,” the IBM ISS report states.

The report also found that spam messages are overwhelmingly sent in English, with only the languages of German, Korean, Portuguese and Russian appearing in any amount worth noting.

Geographically, IBM ISS points to South Korea (16.33%), Spain (14.71%), the United States (10.95%), France (9.92%), Brazil (6.76%), Israel (6.41%), Germany (5.27%), Italy (4.34%), Poland (3.28%) and Argentina (2.64%) as source countries with the greatest measured volumes of phishing email transmitted.

Top phishing target countries, where the most phishing email is received, are said to be the United States (71.37%), United Kingdom (4.96%), Germany (4.58%), Australia (2.67%) and Canada (2.67%).

The report also takes a stab at interpreting growth in unwanted content, including violence and crime, pornography, computer-related crime and drug-dealing sites. In terms of websites, the US tops the list in every category and accounts for more than 50% in each case, according to the IBM report.

When it comes to the most frequently seen malware, the Downloader Trojan turned up the most in 2006, according to IBM's report.