Internet users have been urged to use other browsers as Explorer problems persist.
The company has urged people to be vigilant while it investigated and prepared an emergency patch to resolve it. Users have been encouraged to use the Firefox, Opera, Chrome and Safari browsers by security experts, as they are not vulnerable to the flaw Microsoft has identified.
In a security advisory alert about the flaw, it said: “Microsoft is continuing its investigation of public reports of attacks against a new vulnerability in Internet Explorer.” It claims to have detected attacks against IE 7.0 but said the ‘underlying vulnerability' was present in all versions of the browser.
Speaking to the BBC website, John Curran, head of Windows at Microsoft UK, said: “It would not be advisable to send people from one vulnerability to multiple vulnerabilities.”
Steve Moyle, founder and CTO of Secerno, said: “This is time for people to take less care and a great time for hackers to take advantage. This attack is a chain of vulnerabilities that can be exploited by the hacker as every part is fairly robust but by chaining them together it allows the hacker to access databases and ultimately networks, which is a massive consequence. As databases are poorly-defended, the hacker can appear on the network as a trusted name.
“The general case is you don't want everyone using one of everything, hackers will find one way into the system so Microsoft is finding a way to spread the risk around. Firefox is not more secure than others, but in this particular case there is a specific Microsoft vulnerability that can be chained together. If you can find a way to break a link it will break the chain.”