Microsoft Internet Explorer Unspecified showHelp Zone Bypass Vulnerability



Date Discovered

October 12, 2004


Microsoft Security Bulletin MS04-038 includes fixes to address an unspecified vulnerability in Internet Explorer that may permit elevation of zone privileges by bypassing from the Internet Zone to the Local Zone. The vendor has stated that additional security verifications have been added to prevent the showHelp DHTML method from being abused by a malicious Web site to load HTML Help files in the context of the Local Zone. It is unclear at this point whether they mean HTML Help files that already exist on the system or HTML Help files that originate from a remote source. Although unconfirmed, this could be related to the following unspecified vulnerability that was addressed in Windows XP SP2/BID 10897 ( Microsoft Windows XP SP2 Released - Multiple Vulnerabilities Fixed): - HTML Help Update to Limit Functionality When It Is Invoked with the window.showHelp( ) Method This is likely similar to earlier issues that have been reported in showHelp, such as BID 9320. Microsoft has not released further details about this vulnerability.

Technologies Affected

  • Avaya DefinityOne Media Servers
  • Avaya IP600 Media Servers
  • Avaya Modular Messaging (MSS) 1.1.0
  • Avaya Modular Messaging (MSS) 2.0.0
  • Avaya S3400 Message Application Server
  • Avaya S8100 Media Servers
  • Microsoft Internet Explorer 5.0.1
  • Microsoft Internet Explorer 5.0.1 SP1
  • Microsoft Internet Explorer 5.0.1 SP2
  • Microsoft Internet Explorer 5.0.1 SP3
  • Microsoft Internet Explorer 5.0.1 SP4
  • Microsoft Internet Explorer 5.5
  • Microsoft Internet Explorer 5.5 SP1
  • Microsoft Internet Explorer 5.5 SP2
  • Microsoft Internet Explorer 6.0
  • Microsoft Internet Explorer 6.0 SP1
  • Microsoft Internet Explorer 6.0 SP2 do not use


Run all software as a nonprivileged user with minimal access rights.
All non-administrative tasks, such as reading email and browsing the Web, should be performed as an unprivileged user with minimal access rights. This will limit the consequences of client-side vulnerabilities.

Do not follow links provided by unknown or untrusted sources.
Web users should be wary of visiting Web sites of questionable integrity or following links provided by unfamiliar or untrusted sources.

Set web browser security to disable the execution of script code or active content.
Disabling support for client-side scripting and Active Content, especially with regards to the Internet Security Zone, will help in limiting exposure to this and other client-side vulnerabilities.

Microsoft has released a cumulative update for supported versions of Internet Explorer to address this and other vulnerabilities. Avaya has released an advisory that acknowledges this vulnerability for Avaya products. Customers are advised to follow Microsoft.s guidance for applying patches. Please see the referenced Avaya advisory at the following location for further details:



This issue was announced by Microsoft.

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