A security company is claiming to have discovered a set of 10 major security flaws in Microsoft Corp.’s Windows XP Service Pack 2, bypassing many of the security measures the update puts into place.
According to Finjan Software Inc., an attacker could exploit the flaws to execute malicious code on a user’s system by luring the user to a specially crafted Web page. Finjan has made the exploit’s full technical details available to Microsoft but refused to make them public until the software giant has developed patches for them.
However, Microsoft has said its initial analysis of the flaws showed that they may not be as serious as the security firm purports. “Our early analysis indicates that Finjan’s claims are potentially misleading and possibly erroneous regarding the breadth and severity of the alleged vulnerabilities in Windows XP SP2,” a Microsoft spokesperson told Techworld. “Microsoft encourages Finjan to abide by the principles of responsible disclosure and to decline to provide further comment or details on the alleged vulnerabilities until Microsoft is able to complete its investigation.”
Finjan, which sells security software it claims would prevent the holes being used, had said the flaws have several specific effects: allowing a Web page to access a local file, elevating the privileges of code downloaded from the Internet, and bypassing the features SP2 uses to alert users of the download and execution of execute files. “By exploiting all vulnerabilities discovered in SP2 by Finjan, attackers can silently and remotely take over an SP2 machine when the user simply browses a Web page,” Finjan said in a statement.
Microsoft may be dubious about the bugs’ effects, but Finjan said it stands behind its claims. “We would not publish this kind of information unless we were 100 per cent sure,” said Tim Warner, Finjan’s regional sales manager for northern Europe. He said Finjan’s standard procedure was to provide Microsoft with demonstrations for each vulnerability, showing how they could be easily exploited.
However, since no technical details are available, it is impossible to have the company’s findings independently confirmed. The conflicting interests of the two parties are all too apparent. Finjan stands to gain significant publicity from discovering large holes in Microsoft’s heavily hyped security update, whereas Microsoft will seek to downplay any issues until it has patches to fix any holes. Neither is likely to make the details public for commercial reasons.
Warner defended Finjan’s decision to publicize the existence of the SP2 bugs before a patch was available, saying the vulnerabilities were so significant that users needed to be aware of them without delay. “There are some people out there who are thinking ‘I’ve got SP2, therefore I’m safe’,” Warner said. “The point here is that it’s not safe — vulnerabilities will always continue to come out, that’s the nature of the game.”
As to whether a patch would be forthcoming, Microsoft said this depends on the severity of the flaws. “If Microsoft finds any valid vulnerability in Windows XP SP2, Microsoft will take immediate and appropriate action which may include releasing a fix out of band if such action is needed to protect customers,” a spokesperson said.
Danish security firm Secunia criticized Finjan for the unorthodox step of publicizing flaws while they are still being analyzed by Microsoft. “Others, including Secunia, work responsibly (and silently) with Microsoft,” said Secunia chief technology officer Thomas Kristensen. “I see no reason to go out and announce information about flaws in this manner.”
If researchers want to push vendors to be more prompt with issuing patches, there are other ways to go about it, Kristensen said, using as an example eEye Digital Security Inc.’s “Upcoming Advisories” listing. This gives vendors a push without providing potential attackers with clues, Kristensen said.
Finjan’s bugs, should they indeed prove serious, would not be the first to have been found in SP2. In August, shortly after SP2’s release, a researcher going by the moniker “http-equiv” publicized a bug in SP2-patched Internet Explorer which could allow a malicious Web site to plant executable code or script on a user’s PC. Microsoft has patched one variant of this but another, publicized last month, is as yet unpatched. The unpatched variant also allows cross-site scripting.
Users can mitigate the problem by disabling the “Drag and drop or copy and paste files” option in Internet Explorer, disabling active content and setting the “Internet” zone to high security.
Kristensen said that while SP2 fixes many of Windows’ underlying security vulnerabilities, Microsoft could have gone still further. “Certain things in Internet Explorer should have been changed more radically in our opinion,” he said. “It would probably break some functionality, but I think that would be perfectly acceptable considering the number of highly critical vulnerabilities pre-SP2.”
He said it is just a matter of time before more SP2 flaws are found, as researchers and hackers gain a better understanding of how the new technology works. “One serious hole has already been discovered and publicly disclosed. I’m certain we will see more in the near future,” Kristensen said.