In June 2005 Microsoft released a security patch, number 896358, to address a potential security threat entitled Vulnerability in HTML Help Could Allow Remote Code Execution .
The 32 and 64bit versions of the following operating systems were affected:
Microsoft Windows 7
Microsoft Windows Vista
Microsoft Windows 2000
Microsoft Windows XP
Microsoft Windows Server 2003
For more information on this security patch please visit:
http://www.microsoft.com/technet/security/bulletin/ms05-026.mspx
Problem
Once this patch is installed, OpenInsight help files located on a server will become unavailable, I.E. you will not be able to read the help files, as this patch stops the help files from opening. Help files located on your local hard drive are unaffected. The update is included in all current windows service packs and impacts new workstation installations that have not been properly setup to work around the issue.
Solution
There are several possible solutions to this problem, all of which are documented in the Microsoft knowledgebase article "KB896358 which you can read by visiting: http://support.microsoft.com/kb/896358 One of the solutions proposed in this article is called the Less conservative approach . This solution involves adding some registry settings to your Windows PC to enable network help files. The required registry settings for this solution are provided below. You may either merge saved registry settings into your registry or add the registry settings by hand.
Note: You must have Administrator rights on the computer to make changes to the Windows registry.
Adding the Registry Settings by Merging From a File:
1. Download either the 32 or 64bit .REG file that matches your system.
{{kb0271_1.png}} {{kb0271_2.png}}
2. Right click on the downloaded file and choose "Merge"
3. Confirm you want to merge the contents of the file with your registry
4. Reboot when finished
Adding the Registry Settings by Hand:
1. Select Start, and then Run from the Windows Taskbar.
2. Type regedit and press enter to start the Windows Registry tool
3. Navigate to one of the following registry branches depending on if the system is 32 or 64bit
32bit: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x
64bit: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\HTMLHelp\1.x
4. Add the following registry keys
HHRestrictions
ItssRestrictions
5. Add the following DWORD s to the HHRestrictions registry key
MaxAllowedZone = 1
EnableFrameNavigationInSafeMode = 1
6. Add the following DWORD to the ItssRestrictions registry key
MaxAllowedZone = 1
You will need to reboot your computer to enable the changes.
References:
Thanks to Charlie Engler for identifying the cause of the problem and Sean Fitzsimons for providing example registry entries.