Microsoft Security Bulletin MS99-018 - Critical
Patch Available for "Malformed Favorites Icon" Vulnerability
Published: May 27, 1999 | Updated: May 16, 2003
Originally Posted: May 27, 1999
Updated: May 16, 2003
Microsoft has released a single patch that eliminates two security vulnerabilities in Microsoft® Internet Explorer 4.0 and 5. The first potentially could allow arbitrary code to be run on a user's computer. The second potentially could allow the local hard drive to be read. A fully supported patch is available to eliminate both vulnerabilities, and Microsoft recommends that affected customers download and install it, if appropriate.
This update eliminates two vulnerabilities:
- The "Malformed Favorites Icon" vulnerability. The Favorites feature allows IE users to keep a list of their favorite web sites. In IE 5, the Favorites list can contain icons that are supplied by the associated web sites. However, there is an unchecked buffer in the implementation. A specially-malformed icon could overrun the buffer and be used to run arbitrary code on the user's computer. This vulnerability only affects IE 5 when run on Windows 95 or 98; it does not affect Windows NT systems.
- The "Legacy ActiveX Control" vulnerability. An ActiveX control that was used by previous versions of IE also was included in IE 4.0 and IE 5 even though it is not used by either. It could be misused to allow a web site to read the user's local hard drive. The update eliminates the vulnerability by removing the control.
While there are no reports of customers being adversely affected by these vulnerabilities, Microsoft is proactively releasing the patch to allow customers to take appropriate action to protect themselves against it.
Affected Software Versions
Microsoft Internet Explorer 4.0 and 5.0
Note The patch, provided below in What Customers Should Do, will determine the version of IE and the platform on which it is installed, and will apply only the appropriate fix. As a result, the single patch below is appropriate for use by customers who are affected by <B>either or both</B> of the vulnerabilities.
- Malformed Favorites Icon Vulnerability: CVE-1999-0802
- Legacy ActiveX Control Vulnerability: CVE-1999-0917
What Microsoft is Doing
Microsoft has released patches that fix the problem identified. The patches are available for download from the sites listed below in What Customers Should Do.
Microsoft also has sent this security bulletin to customers subscribing to the Microsoft Product Security Notification Service. See The Microsoft Product Security Notification Service for more information about this free customer service.
Microsoft has published the following Knowledge Base (KB) article on this issue:
Microsoft Knowledge Base (KB) article 231450, Update Available for the "Malformed Favorites Icon" Issue in Internet Explorer 5, https:
Microsoft Knowledge Base (KB) article 231452, Update Available for "Legacy ActiveX Control" Issue in Internet Explorer 5, </https:>https:
(Note It might take 24 hours from the original posting of this bulletin for the KB article to be visible in the Web-based Knowledge Base.)
What Customers Should Do
Microsoft highly recommends that customers evaluate the degree of risk that this vulnerability poses to their systems and determine whether to download and install the patch. As noted above, the patch is appropriate for use on systems that are affected by either or both of the vulnerabilities.
The patch can be found at </https:>https:
Please see the following references for more information related to this issue.
- Microsoft Security Bulletin MS99-018, Patch Available for "Malformed Favorites Icon" Vulnerability, https://www.microsoft.com/technet/security/bulletin/ms99-018.mspx.
- Microsoft Knowledge Base (KB) article 231450, Update Available for the "Malformed Favorites Icon" Issue in Internet Explorer 5, </https:>https:.
- Microsoft Knowledge Base (KB) article 231452, Update Available for "Legacy ActiveX Control" Issue in Internet Explorer 5, </https:>https:
Obtaining Support on this Issue
If you require technical assistance with this issue, please contact Microsoft Technical Support. For information on contacting Microsoft Technical Support, please see </https:>https:.
Microsoft acknowledges Flavio Veloso for discovering the "Malformed Favorites Icon" vulnerability and reporting it to us, and Steve Loughran for discovering the "Legacy ActiveX Control" vulnerability and reporting it to us.
- May 27, 1999: Bulletin Created.
- V2.0 (May 16, 2003): Introduced versioning and updated patch availability information.
For additional security-related information about Microsoft products, please visit https://www.microsoft.com/technet/security
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