Guninski finds another hole in MS Exchange security

By George A. Chidi

(IDG) -- Bulgarian bug hunter Georgi Guninski said in an advisory that a security risk is created in interactions between Microsoft's Internet Explorer (IE), Internet Information Server (IIS), and Exchange 2000 software, potentially baring server directories and e-mail to prying eyes.

The advisory, issued Wednesday, said Microsoft's OLE DB for Internet publishing program, a tool used to help Web-publish information stored in databases, gives a scripting interface for accessing and manipulating objects on IIS 5.0 or in Web storage.

"The problem is it allows connecting to arbitrary servers, not only to the server from which the HTML page is loaded," Guninski said in the advisory.

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Additionally, if IIS 5.0 is in the local intranet zone of IE versions 5.0 and later, the browser, by default, automatically authenticates it without prompting the user, Guninski wrote.

While neither confirming nor denying the security risk on Thursday, a spokeswoman from Microsoft's public relations firm Waggener Edstrom Inc. called Guninski's revelation "irresponsible."

"Responsible security researchers work with the vendor of a suspected vulnerability issue to ensure that countermeasures are developed before the issue is made public and customers are needlessly put at risk," she said.

She added that the Microsoft "is thoroughly investigating the report, just as they do with every report they receive of security vulnerabilities affecting Microsoft products." She declined to say when Microsoft would complete its assessment.

Guninski classifies the hole as high risk. Guninski said in the report that he had alerted Microsoft to the problem, and that the company replied that, "visiting malicious Web sites is not a real exploit scenario."

A hacker hoping to exploit the hole would have to create a malicious Web page in order to peek at server directories, Guninski wrote. It is possible to list the directories of arbitrary IIS 5.0 servers to which the browsing user has access.

"Under certain circumstances, it is also possible to read the user's e-mail or folders if it is stored on an Exchange 2000 server with Web storage," he wrote. "It is also possible to create (or probably modify) files on the Exchange 2000 server with Web storage."

Guninski recommended users disable Active Scripting to solve this particular issue.

Guninski discovered several vulnerabilities in Microsoft software last year. His most recent discovery, reported in January, was of a security vulnerability in Microsoft's Windows Media Player 7, a problem with the player's "skins" -- custom decorations for the graphical user interface -- that potentially allows a hacker to get full control over a user's computer.

Microsoft Web sites suffer large scale blackout
January 24, 2001
Worm possibly used against Microsoft had links to China
January 19, 2001
New security hole found in Microsoft Internet Explorer
November 23, 2000
Exchange bug could be exploited for denial-of-service attacks
November 6, 2000
Microsoft security executive promises improvements
July 27, 2000
Microsoft scrambling to fix new Outlook security hole
July 21, 2000

Microsoft, VeriSign warn of security hole
(PCWorld.com)
Patches issued to plug denial-of-service hole in Exchange, IIS
(Network World Fusion)
TCP hole may be more dangerous than first thought
(Computerworld)
Microsoft's fuzzy plans raise Exchange concerns
(Network World Fusion)
Microsoft urging IIS users to patch serious security hole
(Computerworld)
Microsoft shows tools used to debug Win XP
(IDG.net)
New Web page shows who's tracking you
(InfoWorld.com)
Active Directory fix to require significant upgrade
(Network World Fusion)

Microsoft Corp.


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