We have long known that Internet Explorer is one of the most unsafe browsers that are incompatible, although a lot of site designers continue to make pages compatible only with this browser. Among its most severe vulnerabilities are those that allow code injection, since it opens the door to run any program on the targeted machine.

A few days ago Google official acknowledged on his blog have been under attack "highly sophisticated" of Chinese origin on their infrastructure. In its assessment of damages stated intellectual property theft and a limited attack on two counts of mail from GMail, saying they had evidence that the ultimate goal was to obtain information on Chinese activists for human rights. At first there was talk of a vulnerability in Acrobat Reader from Adobe, but after the malware analysis, conducted by the company McAfee, said that it found no evidence so far on a possible new 0-day and in the Adobe Reader. What the researchers did find was an unknown vulnerability in Microsoft's browser, Internet Explorer, which allows running arbitrary code, and could be behind these attacks.

Imagine, if someone can execute arbitrary code on your machine, you may install a backdoor that allows it to take full control of your files, or even use your computer to send spam or attack other computers within the network where you are, for example, your office.

So far they have not released a security update (Microsoft), but is in work release, with 979,352 security alert, you can read more information on the Microsoft Blog.