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Microsoft Internet Explorer Content Advisor contains a buffer overflow

Vulnerability Note VU#222050

Original Release Date: 2005-04-12 | Last Revised: 2005-04-13


A buffer overflow in Microsoft Internet Explorer Content Advisor may allow a remote attacker to execute arbitrary code on a vulnerable system.


The Content Advisor is used to control what content is viewable in Internet Explorer. A buffer overflow exists in the routines that handle Content Advisor files. If an attacker can persuade a user to visit a specially crafted web page the attacker may be able to execute arbitrary code with the privileges of the current user. For more detailed information and for a list of vulnerable software, see Microsoft Security Bulletin MS05-020.


By convincing a user to view an HTML document (e.g., a web page or HTML email message), 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. A user would need to click through a series of Content Advisor setup windows for the attack to be successful.


Apply a patch

Apply a patch as described in Microsoft Security Bulletin MS05-020. Please also note that Microsoft is actively deploying the patches for this vulnerability via Windows Update.

Do not install unsolicited Content Advisor files

This vulnerability could be exploited when a user installs a Content Advisor (.rat) file. Do not open files of this type.

Disable Active scripting and ActiveX controls

To protect against this and other IE vulnerabilities, consider disabling Active scripting and ActiveX controls in the Internet Zone as described in the Malicious Web Scripts FAQ. Consider disabling Active scripting and ActiveX controls in the Local Machine Zone. See Microsoft Knowledge Base Article 833633 for information about securing the Local Machine Zone and 315933 for information about displaying the Local Machine Zone (My Computer security zone) on the Security tab in the Internet Options dialog box.

Note that disabling Active scripting and ActiveX controls in the Internet Zone will reduce the functionality of some web sites. Disabling these features in the Local Machine Zone will reduce the functionality of some programs, including the Help and Support Center in Windows XP.

Read and send email in plain text format

Outlook 2003, Outlook 2002 SP1, and Outlook 6 SP1 can be configured to view email messages in text format. Consider the security of fellow Internet users and send email in plain text format when possible. Note that reading and sending email in plain text will not necessarily prevent exploitation of this vulnerability.

Do not follow unsolicited links

In order to convince users to visit their sites, attackers often use URL encoding, IP address variations, long URLs, intentional misspellings, and other techniques to create misleading links. Do not click on unsolicited links received in email, instant messages, web forums, or internet relay chat (IRC) channels. Type URLs directly into the browser to avoid these misleading links. While these are generally good security practices, following these behaviors will not prevent exploitation of this vulnerability in all cases, particularly if a trusted site has been compromised or allows cross-site scripting.

Vendor Information


Microsoft Corporation Affected

Updated:  April 12, 2005



Vendor Statement

We have not received a statement from the vendor.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


US-CERT has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

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This vulnerability was publicly reported by Microsoft who credits Andres Tarasco of SIA Group.

This document was written by Jeff Gennari and Will Dormann.

Other Information

CVE IDs: CVE-2005-0555
Severity Metric: 4.36
Date Public: 2005-04-12
Date First Published: 2005-04-12
Date Last Updated: 2005-04-13 19:31 UTC
Document Revision: 26

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