Microsoft warns of Poison Ivy in IE web browser

Microsoft Corp has warned of a newly discovered bug in its Internet Explorer web browser that makee PCs vulnerable to attack by hackers.

The software giant has urged customers to download a piece of security software to reduce the risk of infection.

The security flaw present in the Internet Explorer browser of hundreds of millions of users made their systems vulnerable to attacks that could allow hackers to take control of the victim's computer.

The software maker advised customers on its website late yesterday to install the security software as an interim measure, as it sought to buy time to fix the bug and release a new, version of Internet Explorer with enhanced security. The company made no mention of how long that would take, but according to experts quoted by Reuters, it might take a week.

The free security tool, called the Enhanced Mitigation Experience Toolkit, or EMET, is available through an advisory on Microsoft's website: blogs.technet.com/b/msrc/ The posting from Microsoft said the software needed to be downloaded, installed and then manually configured to  protect computers from the newly discovered threat.

Microsoft also advised customers to adjust several Windows security settings to thwart potential attackers, cautioning at the same time that doing so might impact the PC's usability.