ActiveX bugs pose threat to Vista, Microsoft reports

Although computers running Windows Vista are significantly less likely to be infected with attack code than machines running Windows XP, the newer operating system continues to be threatened by Microsoft's own ActiveX browser plug-in technology, according to a report issued Monday by the company.

In the most recent installment of its twice-yearly security intelligence report, Microsoft said that PCs running Windows XP Service Pack 2 (SP2) were more than three times as likely to be infected with malware as computers running Windows Vista SP1. Machines powered by the newest XP security update, SP3, meanwhile, were more than twice as likely to be infected.

According to Microsoft, in the six months from January to June, its Malicious Software Removal Tool (MSRT) cleaned malware from just three Vista SP1 machines per thousand times the tool was run. Meanwhile, during the same period MSRT found and wiped malicious code from 10 Windows XP SP2 systems and eight XP SP3 PCs per thousand executions. Microsoft updates and automatically redistributes the software tool to Windows users each month on Patch Tuesday.

"Our security development processes do pay off," said George Stathakopoulos, the general manager of Microsoft's product security and security engineering group, referring to work the company's put into writing more secure code for its newer software, including Vista. "We're fairly happy where Microsoft is," Stathakopoulos continued, "but ecosystem-wide, we still have a problem."

That's evident from Microsoft's data for the last six months. During that time, while half of the top 10 browser-based attacks against Windows XP machines relied on vulnerabilities in Microsoft's own software, none of the top 10 attacks against Vista systems did. Instead, the overwhelming majority of the browser attacks targeting Vista leveraged bugs in third-party companies' ActiveX controls.

Vulnerabilities in ActiveX, the Microsoft technology used to create add-ins for Internet Explorer (IE), accounted for eight of the top 10 browser-based attacks against Vista in the first half of 2008. A ninth vulnerability could be exploited via ActiveX, among other means.

Two of the eight vulnerability ActiveX controls were part of RealNetworks' RealPlayer media player plug-in; another was part of Apple's QuickTime player. Both vendors have had to repeatedly patch their programs this year. Apple alone has patched a total of 30 QuickTime vulnerabilities in five updates in 2008.

Microsoft's numbers echo data collected by Symantec for the last half of 2007, when ActiveX bugs accounted for 79 percent of all those discovered in browser plug-ins during that period.

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Stathakopoulos defended ActiveX, but acknowledged that it was impossible for Microsoft to police its technology. "You have to enable [add-on] development for the browser," he said. "The question is, how do you extend the browser and at the same time provide guidance to developers on how to write secure [ActiveX controls]?" he said.

The problem is especially evident in China, whose users accounted for 47 percent of all victims of browser-based attacks during the first half of 2008, according to Microsoft. Stathakopoulos blamed Chinese developers for contributing to the ActiveX issue. "I think it's a combination of developers who don't have good security discipline, and [the Chinese market] being a very large target," he said, explaining why Microsoft thought China was particularly hit hard by browser attacks.

US users accounted for 23 percent of all victims of browser-based exploits.

Microsoft is doing more to help developers write more secure code, Stathakopoulos said. In September, the company unveiled a for-fee program, dubbed "SDL Pro Network," where service provider partners consult with businesses to help them apply Microsoft's Security Development Lifecycle practices. Microsoft will also release a pair of free-of-charge tools distilled from its SDL work this month.

He also argued that the company's work to lock down ActiveX in IE was paying off. IE7, for example, blocks many ActiveX controls by default, and requires the user to explicitly agree to their operation. The still-in-beta IE8, meanwhile, has introduced additional ActiveX security features, including the ability to restrict controls to specific domains -- an enterprise intranet, for example.

Symantec's report earlier this year, however, disputed the idea that Microsoft's efforts had done much good. IE7, said Symantec in April, had not had a significant impact on the number of ActiveX vulnerabilities.

"We're going to try to help third-party developers write more secure code," said Stathakopoulos. "But it will be a long, drawn-out problem."

Microsoft's most recent security report can be downloaded from the company's site.