At least one of the vulnerabilities has received the maximum severity rating of critical, the highest possible rating, on all affected operating systems and .Net versions. Microsoft notes that the most severe vulnerability could allow elevation of privileges “if an unauthenticated attacker sends a specially crafted web request to” a target site. Attackers who successfully exploit the issue can “take any action in the context of an existing account on the ASP.NET site, including executing arbitrary commands”.

Security updates are already listed on Windows Update. Windows users who have only installed the Microsoft .Net Framework 4.0 Client Profile may only see important in Windows Update instead of critical ones. That is because ASP.Net, the component that is affected by the critical vulnerability, is not included in this version of the framework.

Most Windows users have configured automatic updates. Users who do not use automatic updates or Windows Update may download the patches from the Microsoft Update Catalog site instead. Please note that you can only open the site in Internet Explorer and not in other browsers.

Microsoft’s Download Center is currently not listing the security updates. It is however likely that they will appear on the site in the next days.

A restart of the computer is not required after applying the patches. The patches will merely stop related services during patches before they are restarted.

Additional information about the security vulnerability are available on the Microsoft Security Bulletin page. This bulletin raises the count to 100 bulletins that have been released by the Redmond company in 2011.

The troubleshooting of .Net Framework issues should begin with an assessment of the installed versions of the Framework on the operating system. The tool for that is the .Net Framework Setup Verification Utility. It supports all versions of the .Net Framework, here is the full list valid as of today:

• .NET Framework 1.0
• .NET Framework 1.1
• .NET Framework 1.1 SP1
• .NET Framework 2.0
• .NET Framework 2.0 SP1
• .NET Framework 2.0 SP2
• .NET Framework 3.0
• .NET Framework 3.0 SP1
• .NET Framework 3.0 SP2
• .NET Framework 3.5
• .NET Framework 3.5 SP1
• .NET Framework 4 Client
• .NET Framework 4 Full

It is important to always run the latest version of the installed .Net Framework on the system. This means that you should run .Net Framework 3.0 SP2 and not .Net Framework 3.0. The setup verification tool scans the computer for installed .Net Framework versions and displays them in a listing. Even better is that it can be used to verify the integrity of those installations.

To verify a .Net Framework installation pick the product from the pulldown menu and select Verify Now. The application scans the system and will display the status of the analysis in the end. The message Product verification succeeded indicates that that scanned .Net Framework version is installed correctly on the system. Two log files are automatically generated, the important log for troubleshooting the framework is the error log. Both log files are stored in the system cache.

The verification needs to be run for every installed .Net Framework version. There are two possibilities now. The first is that all verifications have completed successfully. That’s great as it means that the .Net Framework is working properly and that a corrupt installation is not the cause of the issues experienced on the PC. Users who do not have the latest .Net Framework version installed may consider installing it to see if it resolves the issues they are experiencing.

Users with corrupt or damaged framework installations need to fix those issues before they can run programs that depend on the framework in Windows. There are two possibilities for this. They may want to try and uninstall the damaged frameworks from the “uninstall a program” control panel applet.

This may or may not work depending on the individual situation. The best alternative for this scenario is to remove the full .Net Framework from the system, with full meaning all product versions. It is then possible to reinstall the desired .Microsoft .NET Framework after the old installation has been removed completely from the computer system.

The tool of choice for this procedure is the .NET Framework Cleanup Tool which supports the following product versions.

• .NET Framework – All Versions
• .NET Framework – All Versions (Tablet PC and Media Center)
• .NET Framework – All Versions (Windows Server 2003)
• .NET Framework – All Versions (Windows Vista and Windows Server 2008)
• .NET Framework 1.0
• .NET Framework 1.1
• .NET Framework 2.0
• .NET Framework 3.0
• .NET Framework 3.5
• .NET Framework 4

Please note that the cleanup tool will only offer to remove framework versions that are not part of the operating system. This means for instance that Windows 7 users will only see an option to remove the .NET Framework 4.0 if it is installed and not the versions 2.0, 3.0 or 3.5.

Have another tip on troubleshooting .Net Framework issues? Post it in the comments.

Many programs that are developed for the Windows operating system make use of the framework that needs to be installed before software that uses it can be installed or run. Verifying that the .net Framework has been installed correctly is an important task especially for business environments but also for users who experience error messages or other problems with the net. Framework.

The Microsoft .Net Framework Setup Verification Utility can verify the installed .net Frameworks. It will only display those frameworks that it detects to be installed on the computer system it is executed on.

This limitation to the installed versions can be overridden with a command line parameter.

netfx_setupverifier.exe /q:a /c:"setupverifier.exe /a"

The program can also be run in silent mode which will process the command without showing the graphical user interface.

netfx_setupverifier.exe /q:a /c:"setupverifier.exe /p "

The program will start the verification of the selected .net Framework after selecting one of the available options in the pulldown menu and a click on the Verify Now button. The result will be echoed in the graphical user interface. More interesting for most users is the log file that is created by the program. This log file contains detailed information about the verification steps. It will for instance display all the files that are installed with the selected net Framework and their status.

This log file can be used to analyse problems which usually come down to missing files or Registry entries.

The Microsoft .Net Framework Setup Verification Utility can be downloaded from the developer’s website over at MSDN. The website contains additional information and command line parameters.

It can happen that the uninstallation or repair of a .net Framework installation fails which can have the effect that a new installation wont succeed either. Manually removing the leftovers to be able to install the framework anew is a complex process.

A far better solution would be to run a cleanup tool that will remove all traces of the Microsoft .net Framework from the computer system.

Aaron Stebner’s (via Raymond) Microsoft .net Framework Cleanup Tool is that software program. The portable application scans the computer system for installed .net Framework versions.

It will display them in a list with the option to uninstall a specific .net Framework version or all of them from the computer system. The software developer points out that his application should be used as a last resort if the regular installation or uninstallation of the Microsoft .net Framework fails on the computer.

The Wikiquote Screensaver makes use of yet another Wikipedia site but gives the user more control over what is actually displayed when the screensaver activates. Wikiquotes provides access to a large collection of quotations in several languages.

The screensaver makes use of an interface that can be used to add quotes to the screensaver. At least one quote has to be added before the screensaver starts working at all. This is done by searching for a name or term. A list of matches will then be displayed. By default all are selected to be added to the screensaver’s rotation.

The quotes that have been selected have to be saved in the end. Once that is done they will be displayed when the screensaver becomes active.

The screensaver requires the Microsoft .net Framework 3.5 Service Pack 1 to function. The pack can be downloaded from Microsoft.

What’s your favorite quote? Let me know..

While that did not help I looked through my installed programs to find out which applications could depend on the Framework and the only other programs that I could come up with were the other Microsoft .net Frameworks that were installed on my system. Both the Microsoft .net Framework 3 and 3.5 were also installed on the computer.

I decided to uninstall the other two Frameworks and the only that I could uninstall was the last one, the Framework 3.5. Once that was uninstalled I was able to uninstall the Framework 3.0 and finally, after that I was able to remove the Microsoft .net Framework 2.0.

It seems that the newer Microsoft .net Frameworks depend on older versions that are also installed on the computer. The only viable choice you have if you want to uninstall an older version is to uninstall the newer versions as well and install them again after the old one has been uninstalled.

I never experienced the behavior on my old computer though and it seemed as if the process would not go away on its own. It was there, eating my CPU cycles even after quitting the program installation.

Apparently mscorsvw.exe is precompiling .NET assemblies in the background which can take anywhere from 5 to 10 minutes and then some more for low priority assemblies. So the easiest way to get through it is by sitting it out.

If you want to get rid of it completely immediately you could issue the command ngen.exe executequeueditems. Ngen.exe is located in the Microsoft .net Framework directory in the Windows dir.

The Cumulative Security Update for Internet Explorer patches Internet Explorer 6 and newer versions of Internet Explorer. If the user visits a specially prepared website an attacker can gain the same rights on the Windows system as the user who is currently logged into the system. While this does not affect other browsers and to a lesser extent users who do not use administrative accounts it is still recommended to update the software immediately.

The Vulnerabilities in .NET Framework Could Allow Remote Code Execution patch fixes three security vulnerabilities. Two of them allow remote code execution and one information disclosure. It is again advised to update the system immediately to fix those security holes.