While Internet Explorer still remains the most popular internet browser [mainly due to being only one provided with Windows natively] Nevertheless IE has been riddled with flaws as well as security holes since inception. Microsoft continues to update IE and patch whatever flaws have been determined. A practice that continues to this day.

Many of the issues that affect IE today are as a result of various scripts impact upon the browser. Depending on how they are written it can simply crash IE or perhaps even more incidious use IE as an unwitting partner in a phishing scam such as the example illustrated using the link available at the Secunia website. Additionally you will find links to couple other testing websites. None of these website reportedly install any plugins or save anything to your hard drive. These are only run various scripts to test whether or not your web broswer is vulverable.

The dslreports forums website.
The Testing. OnlyTheRightAnswers website.
The Secunia website.