Apple has taken the place of Microsoft for disclosing more vulnerabilities than any other vendor, according to an IBM security report.

The company rose from second place in 2007 to take the top spot away from Microsoft, which had fallen into third place behind open source content management system Joomla.

Final results were close, according to the IBM X-Force 2008 mid-year report, with Apple achieving vulnerability disclosure score of 3.2 percent, followed by Joomla with 2.7 percent and Microsoft at 2.5 percent.

IBM remained in fourth spot, followed by Sun, a newcomer to the top five, while Oracle and Cisco fell from their former positions to sixth and seventh respectively.

The introduction of a new Common Platform Enumeration (CPE) into the X-Force database introduced PHP-based Joomla, WordPress and Drupal into the top ten disclosure list.

X-Force attributes their appearance to a rise in Web application flaws, predominantly cross-site scripting (XSS) and SQL injection attacks, that account for 51 percent of all vulnerabilities.

The report claimed PHP would have taken forth spot in the 2007 disclosure list if the CPE rules were applied.

"From 2007 to the first half of 2008, vulnerabilities affecting Web server applications accounted for 51 percent of all vulnerability disclosures.

Microsoft held on to the top spot for the number of public exploits, followed by Hewlett Packard and Apple. The three vendors accounted for about half of all exploits found in the top ten list.

Internet Explorer and Mozilla Firefox browsers had a marked drop in critical vulnerabilities from 2007. Both browsers had six memory corruption vulnerabilities, down from 20 and eight respectively in 2007, however Firefox fell short of it's rival with one security zone bypass, and a single miscellaneous vulnerability. Firefox had 11 security zone bypass and four buffer overflow flaws in 2007.

X-Force claims 94 percent of all browser exploits occur within 24 hours of vulnerability disclosure.

X-Force operations manager Kris Lamb said the attacks will be reduced if independent researchers stop publishing exploit code with vulnerability disclosures.

"Without a unified process for disclosing vulnerabilities, the research industry runs the risk of actually fueling online criminal activity," Lamb said.

"There is a reason why X-Force does not publish exploit code for the vulnerabilities we have found, and perhaps it is time for others in our field to reconsider this practice."

Holes in third party virtualisation (VM) software has fallen, according to the study, while unexpected vulnerabilities have risen over the last three years as they are discovered in increasingly complex VM services. Vulnerability research is now focused on complex areas including I/O fuzzing, random opcode generators and static analysis.