Windows 8 a step forward in security, researcher says
Microsoft’s new operating system builds on existing code from previous versions and represents a step forward in security, said security researcher Chris Valasek, who has been examining early releases of Windows 8.
“As a security practitioner, I like the thing they have put in place to make it harder to exploit,” he said. Microsoft has become more security conscious, he said, and the benefits of the new OS probably will outweigh the risks.
Valasek, a senior security researcher at Coverity, has been analyzing Windows 8 since the release of the developer’s version last fall and now is looking at the Consumer Preview that was released in February.
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A release preview version is expected to be made public in June, and the final release is expected in October, although that is subject to change. Valasek will present his findings on the security in the new operating system at the Black Hat Briefings in July.
He said Windows 8 benefits from the fact that, in spite of the new Metro interface that is intended to provide a common look and feel across both mobile and desktop platforms, a lot of the code has carried over from Windows 7. The jump from 7 to 8 is not as great as that from XP to Vista, so developers have been able to mature the code without greatly increasing the attack space offered by new code.
At the same time, new defenses have been added.
“The most interesting thing is, they have put many more exploit mitigation technologies into Windows 8,” Valasek said.
These technologies address and protect against the common characteristics of vulnerabilities so that possibly malicious actions can be identified, examined and blocked even if the specific vulnerability has not been identified.
“They are willing to accept that there are going to be software vulnerabilities,” he said. “But the exploit mitigation makes it harder to turn a vulnerability into an exploit and compromise the machine, raising the bar for attackers.”
Microsoft has been using exploit mitigation since the release of Service Pack 2 for XP. “They have made leaps and bounds since then,” he said. “It takes a lot of effort to make them work without compromising other Microsoft and third-party software.”
Several security enhancements are being included for the mobile environment that Windows 8 will be operating in, Valasek said. There will be an app store for the OS, and Microsoft has added more granular controls on how these applications can operate.
With the current low-medium-high integrity levels, applications with lower integrity are not allowed to write to areas of higher integrity in an effort to block the installation and spread of malicious code. But it does not prevent a low-integrity application from stealing information by reading higher-level processes.
Under Windows 8, applications will have policies declaring their activities and purposes and these will be used to restrict operations so that covert activities will be harder to carry out. Valasek said this is a step forward in controlling malicious applications, although it does not eliminate the risk. “The problem isn’t going to be solved overnight,” he said.
There also will be two versions of Internet Explorer 10 on the new OS. When operated with the Metro interface for mobile environments, it will support only HTML5, the latest version of the markup language for Web content, with no support for third-party plug-ins such as Flash and Java that have been the target of malicious exploits.
“That really takes a lot of risk away from Internet Explorer,” Valasek said. “They will probably be giving some things up” in this mode, but IE 10 with support for plug-ins can be run on desktop computers.
Microsoft has made thousands of changes in pre-release versions of Windows 8, and additional changes are likely before the final release.
“They are not minor details by any means,” Valasek said of changes made to date. “But they are not life-altering.” He said he expects that future changes made before the final release are likely to shore up security rather than expose more vulnerabilities.