MS12-024: Vulnerability in Windows could allow remote code execution: April 10, 2012

Known issues with this security update

• After you install this security update on a computer that is running Windows Vista or Windows Server 2008, the computer name might change to "MINWINPC." When this problem occurs, you cannot log on to computer even if you restart the computer. When you try to log on, you may receive an error message that resembles the following:
  
  
  The username or password is incorrect.
  
  
  This issue occurs when you install the security update on a system that has partly corrupted data or when the following registry key does not exist:
  
  
  HKEY_LOCAL_MACHINE\SCHEMA\wcm://Microsoft-Windows-CoreOS?##########
  Note In this example, ########## may be any text.
  
  If the HKEY_LOCAL_MACHINE\SCHEMA registry subkey does not exist, you can verify the issue by loading the %SystemRoot%\system32\SMI\Store\Machine\SCHEMA.DAT file.
  
  Important
  This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
  
  322756 How to back up and restore the registry in Windows
  
  
  To resolve this issue, follow these steps:
  
  1. Start the computer in safe mode.
  2. Click Start, click Run, type regedit in the Open box, and then click OK.
  3. Locate and then click the following subkeys in the registry:
     
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ComputerName\ActiveComputerName
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ComputerName\ComputerName
  4. Change the ActiveComputerName and ComputerName REG_SZ registry entries so that they use the correct computer name.
  5. Exit Registry Editor, and then restart the computer.
  To avoid this issue, run the System Update Readiness Tool before you install the security update. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
  
  947821 Fix Windows Update corruption errors such as 0x80070002 and 0x80070057
  
  How to determine whether the problem is resolved
  
  If the tool fixed this problem, the following entry is added to the %WinDir%\Logs\CBS\CheckSUR.log file:

   
  Recreated missing key: wcm://Microsoft-Windows-CoreOS?...\metadata\elements\ComputerName
   

  
  
  The tool will add the following entries to the CheckSUR.log file whether it actually fixes the problem or not:
  
  

   
  Recreated value: @_type. 
  Recreated value: @dataOnly. 
  Recreated value: @default. 
  Recreated value: @description. 
  Recreated value: @displayName. 
  Recreated value: @handler. 
  Recreated value: @legacyName. 
  Recreated value: @legacyType. 
  Recreated value: @migrate. 
  Recreated value: @scope. 
  Recreated value: @xsd:type. 

• After you install this security update on a Windows Server 2003 SP2-based terminal server, Remote Desktop Protocol (RDP) clients or Independent Computing Architecture (ICA) clients may be unable to connect to the terminal server. To resolve this problem, install hotfix 958476.
  
  For more information about hotfix 958476, click the following article number to view the article in the Microsoft Knowledge Base:
  
  958476 RDP clients and ICA clients cannot connect to a Windows Server 2003-based terminal server after hotfix 938759 is applied to the server
• This update changes the way that the Windows Authenticode Signature Verification function performs Windows Authenticode signature verification when portable executable (PE) files are verified. PE files are considered "unsigned" in the following scenarios:
  
  • Windows can identify content that does not comply with the Authenticode spec in areas of the file. This fix may affect some third-party installers.
    
    Solution If you are using an installer that is affected by this fix, we recommend that you use an installer that extracts content from only the validated parts of the signed file.
    
    
  • Additional content is appended to the file after the signature is applied.
    
    Solution Application signing should be the final step in the build process before the binaries are released. For more information about application signing and Windows Authenticode, go to the following Microsoft Developer Network (MSDN) webpage:
    Windows Authenticode Portable Executable Signature Format