Exploiting Another Vulnerability

By Matt Hines  |  Posted 2006-08-08 Print this article Print

Another vulnerability patched in the release involves Windows DNS resolution code, which could also be attacked using remote code execution. By exploiting the glitch, the company said an attacker could install programs or create new accounts with full user rights.
The issue specifically involves vulnerabilities linked to a DNS Client buffer overrun and an issue with its Winsock Hostname function.

Microsoft issued a bulletin that promises to fix a flaw in Windows management console that could be targeted for remote code execution attacks. A bulletin was released with a patch for a problem in Windows HTML help functions, which may leave computers running the software vulnerable to remote code execution as well. Using a buffer overrun in the HTML Help ActiveX control, an attacker exploiting the flaw could allow remote code execution on an affected system.

By constructing a malicious Web page to take advantage of the issue, an outsider could potentially allow remote code execution if a user visited that page, allowing them to take control of the individuals system and escalate user privileges. Microsoft said that Internet Explorer on Windows Server 2003 runs by default in a restricted mode that could mitigate the vulnerability for users of the program.

Another issue addressed several issues in Windows software kernel that could also lead to remote code execution exploits.

Among the critical Office vulnerabilities addressed in the newest security patch collection was a pair of issues in the PowerPoint presentation software, and a flaw in Microsoft Visual Basic for Applications, both of which could leave computers open to remote code execution attacks. Office applications have been a regular target for so-called zero-day attacks.

In the case of the PowerPoint bulletin, Microsoft addressed one issue that could be exploited when a file containing a malformed shape container is parsed by the application. Such a file might be included in an e-mail attachment or hosted on a malicious Web site, allowing an attacker to exploit the vulnerability by constructing a specially crafted PowerPoint file that could allow remote code execution.

The second PowerPoint glitch relates to malformed records, which, when parsed by the program, could leave it open for exploit. Such a file might also be included in an e-mail attachment or hosted on a malicious Web site allowing an attacker to exploit the vulnerability by constructing a specially crafted PowerPoint file that could allow remote code execution.

The company has already confirmed that the PowerPoint vulnerability has been used in targeted attacks that are believed to be linked to corporate espionage in the Far East.

The vulnerability in Visual Basic for Applications exists in the manner that the program checks the document properties that a host application passes to it when opening a document and could also allow an outsider to take complete control of an affected system.

The company did not offer a bulletin for its Excel spreadsheet program, for which a known vulnerability still exists. In the July patch batch, Microsoft released a mega update for the Excel spreadsheet program and warned that the flaw could let malicious hackers take "complete control of the vulnerable client workstation."

Among the three "important" flaws in Windows addressed by the new batch of security bulletins were glitches in Explorer and the operating systems Hyperlink Object Library, which could permit remote execution attacks, and an issue in the softwares kernel that could lead to elevation of privileges if exploited.

John Lambert, senior group manager in Microsofts SWI (Secure Windows Initiative), which is responsible for reducing the number of vulnerabilities present in Microsofts next generation Vista operating system, told attendees of the recent Black Hat security conference that the company is making significant headway with its efforts.

Speaking at the conference in Las Vegas on Aug. 2, Lambert said that Microsoft has learned many valuable lessons over the years in how to better secure its products, specifically as Windows has been assailed by viruses that use code vulnerabilities to wreak havoc for end users. Microsofts SDL (Security Development Lifecycle) and other code analysis efforts are expected to result in the most secure operating system the firm has ever released.

"We learned a lot of things during the Windows security standoff, that doing threat modeling after the code is written is not the best way to do modeling," Lambert said. "We know there will be defects that make it through [into Vista] despite our best efforts, but we wanted to embark on effort to reduce the number of liabilities to prevent future exploits."

Check out eWEEK.coms for the latest security news, reviews and analysis. And for insights on security coverage around the Web, take a look at eWEEK.com Security Center Editor Larry Seltzers Weblog.


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