Software Engineering Institute

RealNetworks RealPlayer is a multimedia application that allows users to view local and remote audio/video content. The RealPlayer ActiveX control allows web authors to embed the RealPlayer application in HTML documents and have control over it. One of the exported functions of the RealPlayer ActiveX control is HandleAction, which executes a method or action. When the HandleAction function is used to call the ShowPreferences method, the RealPlayer preferences dialog is displayed, showing the specified category and page.

The ShowPreferences method concatenates its two arguments and then makes an unchecked call to sprintf(). By passing long arguments to ShowPreferences, an attacker can cause a stack-based buffer overflow to occur. Any browser that supports ActiveX may be affected, including IE and other software that uses MSHTML.

By convincing a user to view an HTML document (e.g., a web page or HTML email messsage), an attacker could execute arbitrary commands or code with the privileges of the user. The attacker could take any action as the user. If the user has administrative privileges, the attacker could take complete control of the user's system.

Install update
Install an update, as specified by the RealNetworks security advisory.

Disable Active scripting and ActiveX controls

To protect against this and other vulnerabilities in ActiveX controls, consider disabling Active scripting and ActiveX controls in the Internet Zone as described in the Malicious Web Scripts FAQ. Note that disabling Active scripting and ActiveX controls in the Internet Zone will reduce the functionality of some web sites.