Microsoft Corp is rushing to fix a bug in its widely used Internet Explorer web browser after a computer security firm disclosed the flaw over the weekend, saying hackers have already exploited it in attacks on some U.S. companies.
PCs running Windows XP will not receive any updates fixing that bug when they are released, however, because Microsoft stopped supporting the 13-year-old operating system earlier this month. Security firms estimate that between 15 and 25 percent of the world’s PCs still run Windows XP.
Microsoft disclosed on Saturday its plans to fix the bug in an advisory to its customers posted on its security website, which it said is present in Internet Explorer versions 6 to 11. Those versions dominate desktop browsing, accounting for 55 percent of the PC browser market, according to tech research firms.
Cybersecurity firms have said that a sophisticated group of hackers have been exploiting the bug in a campaign dubbed “Operation Clandestine Fox.”
It’s a campaign of targeted attacks seemingly against U.S.-based firms, currently tied to defense and financial sectors It’s unclear what the motives of this attack group are, at this point. It appears to be broad-spectrum intel gathering.
Microsoft said in the advisory that the vulnerability could allow a hacker to take complete control of an affected system, then do things such as viewing changing, or deleting data, installing malicious programs, or creating accounts that would give hackers full user rights.
Yet other groups of hackers are now racing to learn more about it so they can launch similar attacks before Microsoft prepares a security update.
Windows XP users will not benefit from that update since Microsoft has just halted support for that product.
Microsoft said that it advises Windows XP users to upgrade to one of two most recent versions of its operating system, Windows 7 or 8.
