Windows 10 will have a new browser that's not Internet Explorer

Importantly, Nigro notes that the new browser would be the default. Longtime Microsoft observer Mary Jo Foley at ZDNet expanded on the tweet, citing unnamed sources who said Internet Explorer 11, the default browser in Windows 8.1, would still be present for backward compatibility.

The new browser is codenamed "Spartan," according to Foley.

Spartan will look and feel more like Chrome and Firefox, however, and it will support extensions, according to Foley's report. The "lightweight" browser will be available on both desktop and mobile devices in Windows 10.

The switch from IE to Spartan appears to be more an exercise in rebranding rather than a big technical change. The new browser will still use Microsoft's Chakra JavaScript engine as well as its Trident rendering engine, Foley says, rather than a nonproprietary engine such as WebKit. (Apple's Safari uses WebKit and Google Chrome is based on a "fork" of the open-source software called Blink.)

Microsoft is due to reveal many of the new features in Windows 10 at a Jan. 21 event in the company's hometown of Redmond, Washington. Spartan may make its formal debut there, but the general release of Windows 10 isn't expected until the fall, so it may come at a later date.

Rebranding the official Windows browser makes a great deal of sense. Internet Explorer has a poor reputation among developers and users, much of it rooted in Microsoft's traditional preference for proprietary tools over open standards. Although that stance has changed considerably since the early days of IE, the stigma is so great that Microsoft recently made an ad explaining that the browser's poor reputation isn't deserved.

          

Still, IE took some time to adopt certain standards (such as WebGL) and it suffers from a non-intuitive split experience in Windows 8 and 8.1, with one browser for the desktop and another for the "Modern" UI. In addition, the longtime head of IE, Dean Hachamovitch, left Microsoft earlier in December.

Microsoft Rushes to Fix Browser After Attacks; No Fix for XP Users

BOSTON — 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 firm NetMarketShare.

Cybersecurity software maker FireEye Inc said that a sophisticated group of hackers have been exploiting the bug in a campaign dubbed "Operation Clandestine Fox."

FireEye, whose Mandiant division helps companies respond to cyber attacks, declined to name specific victims or identify the group of hackers, saying that an investigation into the matter is still active.

"It's a campaign of targeted attacks seemingly against U.S.-based firms, currently tied to defense and financial sectors," FireEye spokesman Vitor De Souza said via email. "It's unclear what the motives of this attack group are, at this point. It appears to be broad-spectrum intel gathering."

He declined to elaborate, though he said one way to protect against them would be to switch to another browser.

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.

FireEye and Microsoft have not provided much information about the security flaw or the approach that hackers could use to figure out how to exploit it, said Aviv Raff, chief technology officer of cybersecurity firm Seculert.

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, Raff said.

"Microsoft should move fast," he said. "This will snowball."

Still, he cautioned that Windows XP users will not benefit from that update since Microsoft has just halted support for that product.

The software maker said in a statement to Reuters that it advises Windows XP users to upgrade to one of two most recently versions of its operating system, Windows 7 or 8.