By Glenn Chapman
San Francisco: Microsoft on Wednesday released an emergency patch to fix a perilous software flaw allowing hackers to hijack Internet Explorer browsers and take over computers.
The US software giant said security update MS08-078 addresses a vulnerability cyber-criminals can exploit to their advantage.
“Microsoft encourages all IE customers to test and deploy this update as soon as possible,” said Microsoft security response communications head Christopher Budd.
The threat led Microsoft to mobilize security engineering teams worldwide to deliver a software cure “in the unprecedented time of eight days.”
According to researchers at software security firm Trend Micro, attacks based on the vulnerability in the world’s most popular Web browser were spreading “like wildfire” with millions of computers already compromised.
Microsoft typically releases patches for its software on the second Tuesday of each month and rushing this fix to computer users out-of-cycle is testimony to the severe danger of the threat, according to Trend Micro.
“People should run, not walk, to get it installed,” said Trend Micro advanced threat researcher Paul Ferguson. “This vulnerability is being actively exploited by cyber-criminals and getting worse every day.”
The IE software patch will be automatically applied to hundreds of millions of personal computers due to standard update settings in the machines, according to Microsoft Security Response Alliance director Mike Reavey.
Wednesday morning, business networks using IE began getting the critical fix through routine patching processes.
Reavey said Microsoft went into “emergency response” mode on December 9 after it first learned of the attacks on IE browsers.
A day later, Microsoft published a security advisory that “listed workarounds that blocked all known attacks.”
“Over the course of the next eight days, this advisory was updated five times, adding newer workarounds and mitigations,” Reavey said. “We also continually monitored the threat environment, noting when the attacks began to change in nature and scope.”
Trend Micro has identified about 10,000 websites that have been infected with malicious software that can be surreptitiously slipped into visitors’ unprotected IE browsers to take advantage of the flaw.
A major Internet portal in Taiwan is among the legitimate websites unknowingly tainted with malicious software aimed at IE’s weak spot, according to Ferguson.
Hackers can take control of infected computers, steal data, redirect browsers to dubious websites, and use machines for devious activities such as attacks on other networks, according to security specialists.
“What makes this so insidious is it takes advantage of a big gaping hole of IE, which has the largest install base of any browser on the market,” Ferguson said.
IE is used on nearly three-quarters of the world’s computers, according to industry statistics from November.
Reavey said the patch consists of more than 300 distinct updates for more than half-a-dozen versions of IE in scores of languages.
Analyst Rob Enderle of Enderle Group in Silicon Valley said it was “amazing” that Microsoft was able to turn out a complex critical fix in a week when such jobs typically can take a month or longer of intense work.
“Even with that, the release Emergency Response process isn’t over,” Reavey said. “There is additional support to customers and additional refinement of our product development efforts.”
Trend Micro urges IE users to heed precautionary advice from Microsoft, or avoid using the browsers, until the patches are applied.
The “exploit” is similar to one used recently to steal user names, passwords and other information from people playing online games in China, according to Trend Micro.