On Wednesday, Microsoft released a security advisory warning users of active attacks using a previously unknown bug in Internet Explorer (IE) that affects users of versions six, seven of the browser.

FORBES: Criminal Exploits Targeting New Bug In Old Internet Explorer Versions

The bug revolves around the way that IE manages a computer's memory when processing Cascading Style Sheets - a widely used technology that defines the look and feel of pages on a website.

BBC: Microsoft warns on IE browser bug