Microsoft explains patch cycle

Microsoft has issued eight security updates for its software products including five with the most serious 'Critical' rating.

Programs affected include Internet Explorer, Excel and the Windows operating system.

Anyone who owns a PC running the Windows OS is advised to enable Automatic Updates on their PC or visit the Microsoft Update website as soon as possible to download and apply the patches.

Details of the new patches were released along with an explanation to why it can sometimes take a long time for Microsoft to issue fixes even when vulnerabilities are being actively exploited.

"When we here at Microsoft are asked this question: our answer is 'we want to get this right'. Or to put it another way, we are constantly asking ourselves during any given release cycle 'are we doing the right thing for our customers?'" said Microsoft's Security Response Centre Team in a blog post.

The defence of its system comes after Microsoft was widely criticised for not releasing the patch for the vulnerability in Excel sooner, even though it knew the flaw had been exploited by cybercriminals.