Microsoft Warns of Flaws in ActiveX Control

The flaws, which affect several popular applications, let an attacker run code and read files on a remote machine.

There are three security vulnerabilities in an ActiveX control included in several of Microsoft Corp.s most popular applications that give an attacker the ability to execute code and read files on a remote machine.

The flaw itself is in the Office Web Components (OWC) 2000 and 2002 software, which is included with Office 2000 and XP, BackOffice Server 2000, Internet Security and Acceleration Server 2000 and several other Microsoft applications. With OWC, users get limited Office functionality in a Web browser without having to install the entire Office application.

Each of the three vulnerabilities can be exploited either with a Web page or an HTML mail message. They are all the result of implementation errors in functions that the Active X controls expose.

Resource Library:

The flaw in the Host () function—which provides access to application object models on a users system—could enable an attacker to open an Office application on a users system and use commands that would execute operating-system commands as the user, Microsoft said in an advisory released Wednesday night.

The LoadText () function is used to load text into a browser window. The flaw allows an attacker to circumvent a safeguard that ensures Web pages can only load text that they host. An attacker can specify a text source within the Web pages domain and then use a server-side redirect of the text to a file on a users system.

The attacker could them read any file on the compromised machine.

There is also a problem in the Copy()/Paste() functions, which ignore a security setting in Internet Explorer. The result is that an attacker can access the copy buffer and read any text it contains.

The patch for these vulnerabilities is available here.

Other affected applications include BackOffice Server 2000, BizTalk Server 2000 and 2002, Commerce Server 2000 and 2002, Money 2002 and 2003, Project 2000 and Project Server 2002 and Small Business Server 2000.

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