Microsoft has discovered a new bug in its Internet Explorer (IE) web browser which will make PCs vulnerable to a hack attack. The company has advised users to download temporary security software to prevent the infection.

The company has warned that the new bug could affect hundreds of millions of Internet Explorer users but installation of its Enhanced Mitigation Experience Toolkit would prevent the infection until finds an updated, more secured software version. However experts cautioned the new software must be downloaded and manually configured, which may seem difficult to many ordinary customers.

A few security experts advised users to transform to alternate browsers, including Google Chrome or Mozilla Firefox, until the bug is fixed.

Microsoft has also advised customers to amend several Windows security settings to thwart potential attackers, while cautioning that it could have an impact on the PC’s usability.

The bug was discovered by Luxembourg-based researcher Eric Romang, when his PC got infected by malicious software called Poison Ivy which hackers unleash to steal data or obtain remote control of PCs.

In August 2012, Internet Explorer was second-most widely used browser globally with 33% market share following Chrome, which had 34% of the market during the month.