Microsoft revealed on Tuesday that around 340 million PCs worldwide use an outdated version of their browser software.

The statistic equates to around 24% of all browsers running old code. Microsoft chose to highlight the issue in a blog post on Tuesday, noting that a large number of attacks are directly linked to the use of an out-of-date browser. Internet Explorer 6 and 7 account for 15.2% of all out of date browsers. Google’s Chrome browser, which uses automatic updates to push users onto new versions, accounts for just 1.7% of all old browser versions.

Microsoft is launching YourBrowserMatters.org on Tuesday to highlight the risk of socially engineered malware in old browsers. Microsoft has been working with the Anti-Phishing League, Identity Theft Council, and Online Trust Alliance, to raise awareness of the issues around using an old browser. “YourBrowserMatters.org is a resource for anyone who wants to improve their online security and increase their protection from socially engineered malware threats like phishing attacks,” said Microsoft’s director of Internet Explorer marketing, Roger Capriotti in a blog post on Tuesday. “These attacks are particularly nefarious because they manipulate people into taking actions, such as downloading software that may harm them or their PC by corrupting their computer with a virus, collecting confidential information, or stealing files.”

YourBrowserMatters.org serves as a portal for end users to test their browser security. Microsoft will rank each browser from 0-4 on a scale system. The ranking system uses data from various third parties to asses the important aspects of browser security. The site will also encourage users to upgrade to the latest version of their browser. “We hope they choose IE9 because among other things, it blocks more malware than any other browser out there,” said Capriotti. “The bottom line is we simply want people to protect themselves by knowing that a modern browser is the first line of defense online.”