Last year, 55% of all the computer security vulnerabilities disclosed affected Web applications, and 74% of these had no patch.

So says IBM in its 2008 X-Force Trend and Risk report, released Monday, which paints a dire picture of online computer security.

"Certain types of corporate applications, namely custom-built software like Web applications, remain a highly profitable and inexpensive target for criminal attackers," the report states. "The sheer number of new vulnerabilities, the majority of which have no available patch, coupled with the hundreds of thousands of custom Web applications that are also vulnerable (but never subject to a vulnerability disclosure, much less a patch), continue to be the Achilles' heel of corporate security."

The risk IBM sees is that as legitimate sites become compromised, customer trust becomes collateral damage.

It's worth bearing in mind that when you're a hammer, everything looks like a nail, and when you're selling security, everything looks like a threat. Even so, barring statistical chicanery, the numbers reported by IBM tell a sorry tale.

There were 13.5% more vulnerabilities recorded in 2008 than in 2007. By the year's end, 53% of reported vulnerabilities had no vendor-supplied patch. And that's to say nothing of the 46% of vulnerabilities from 2006 and 44% from 2007 that also remained unpatched.

Trojans targeting online games or online banks represented 46% of all malware.

Such figures might be more easily brushed aside were it not for recent high-profile security failures attributable to malware, like the Heartland Payment Systems data breach or the Downandup/Conflicker worm.

And keep in mind that IBM isn't alone in pointing out the vulnerability of Web applications. Security researchers at AVG Technologies recently said that in the past three months, the number of new infected Web sites grew by 66%, from 100,000 to 200,000 per day to 200,000 to 300,000 per day. And, according to Websense, 70 of the top 100 Web sites during the second half of 2008 either hosted malicious content or contained a link designed to redirect site visitors to a malicious Web site.

The most popular form of attack now is an old one. SQL injection attacks, which have been around for almost a decade, surged 134%, dethroning cross-site scripting as the most popular way to assault Web applications. IBM notes that at the beginning of 2008, there were a few thousand SQL attacks per day. By the end of the year, there were several hundred thousand SQL attacks per day.

"SQL injection vulnerabilities are plentiful and easily discovered," IBM's report explains. "It's also possible to use Web search engines such as Google to find sites running vulnerable applications, and there are many publicly available tools that can test for SQL injection, including some plug-ins for Firefox."