===================================================================== CERT-Renater Note d'Information No. 2008/VULN282 _____________________________________________________________________ DATE : 09/07/2008 HARDWARE PLATFORM(S) : / OPERATING SYSTEM(S) : Windows Vista, Windows Server 2008 running Windows Explorer. ====================================================================== KB950582 http://www.microsoft.com/technet/security/bulletin/ms08-038.mspx ______________________________________________________________________ Vulnerability in Windows Explorer Could Allow Remote Code Execution (950582) This security update resolves a publicly reported vulnerability in Windows Explorer that could allow remote code execution when a specially crafted saved-search file is opened and saved. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. This security update is rated Important for all supported editions of Windows Vista and Windows Server 2008. For more information, see the subsection, Affected and Non-Affected Software, in this section. The security update addresses these vulnerabilities by modifying the way that Windows Explorer parses saved searches. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information. Recommendation. Microsoft recommends that customers apply the update at the earliest opportunity. Affected Software: - Windows Vista and Windows Vista Service Pack 1 - Windows Vista x64 Edition and Windows Vista x64 Edition Service Pack 1 - Windows Server 2008 for 32-bit Systems (Windows Server 2008 Server Core installation affected) - Windows Server 2008 for x64-based Systems (Windows Server 2008 Server Core installation affected) - Windows Server 2008 for Itanium-based Systems Non-Affected Software - Microsoft Windows 2000 Service Pack 4 - Windows XP Service Pack 2 and Windows XP Service Pack 3 - Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2 - Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2 - Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service Pack 2 - Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems Vulnerability Information Windows Saved Search Vulnerability - CVE-2008-1435 A remote code execution vulnerability exists when saving a specially crafted search file within Windows Explorer. This operation causes Windows Explorer to exit and restart in an exploitable manner. Workaround Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality. Workaround 1 Temporarily change the file type associated with the “.search-ms” file extension. Enter the following command at an elevated command prompt: assoc .search-ms=xmlfile Impact of workaround. Saved-search files will open as XML files in Internet Explorer. How to undo the workaround. Enter the following command at an elevated command prompt: assoc .search-ms=SearchFolder Workaround 2 Modify the registry to deny users the ability to open saved-search files or to access the saved search folder. To modify the registry key, follow these steps: Note Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or view the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. 1. Click Start, click Run, type Regedit in the Open box, and then click OK. 2. Locate and then expand the following registry subkey: HKEY_CLASSES_ROOT\SearchFolder Click Edit, and then click Permissions Note Make a note of the permissions that are listed in this dialog box so that you can restore them to their original values at a later time. 3. Click Advanced. 4. Click to clear the Include inheritable permissions from this object's parent check box. You are prompted to click Copy, Remove, or Cancel. Click Remove, and then click OK. 5. You receive a message that states that no one will be able to access this registry key. Click Yes, and then click OK to close the Permissions for SearchFolder dialog box. Impact of workaround. Users will be unable to open saved search files or access the saved search folder. How to undo the workaround. Restore the previously configured permissions on the registry key by clicking to check Include inheritable permissions from this object's parent and then clicking OK two times. Workaround 3 - Unregister the SearchFolder file type. To modify the registry key, follow these steps: Note Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or view the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Using the Interactive Method 1. Click Start, click Run, type Regedit in the Open box, and then click OK. 2. Locate and then click the following registry subkey: HKEY_CLASSES_ROOT\SearchFolder 3. Click the File menu and select Export. 4. In the Export Registry File dialog box, enter SearchFolder_file_association_registry_backup.reg and click Save. Note This will create a backup of this registry key in the My Documentsfolder by default. 5. Press the Delete key on the keyboard to delete the registry key. When prompted to delete the registry key via the Confirm Key Delete dialog box, click Yes. Using a Managed Deployment Script 1. Create a backup copy of the registry keys by using a managed deployment script that contains the following commands: Regedit.exe /e SearchFolder_registry_backup.reg HKEY_CLASSES_ROOT\SearchFolder 2. Next, save the following to a file with a .REG extension, such as Delete_SearchFolder_file_association.reg: Windows Registry Editor Version 5.00 [-HKEY_CLASSES_ROOT\SearchFolder] 3. Run the above registry script on the target machine with the following command from an elevated command prompt: Regedit.exe /s Delete_SearchFolder_file_association.reg Impact of workaround. Double-clicking on a saved search folder will no longer open a window displaying the search results. How to undo the workaround: Using the Interactive Method 1. Click Start, click Run, type Regedit in the Open box, and then click OK. 2. Click the File menu and select Import. 3. In the Import Registry File dialog box, select SearchFolder_file_association_registry_backup.reg and click Open. Using a Managed Deployment Script Restore the original state by running the following command: Regedit.exe /s SearchFolder_registry_backup.reg ====================================================================== ========================================================= Les serveurs de rfrence du CERT-Renater http://www.urec.fr/securite http://www.cru.fr/securite http://www.renater.fr ========================================================= + CERT-RENATER | tel : 01-53-94-20-44 + + 151 bd de l'Hopital | fax : 01-53-94-20-41 + + 75013 Paris | email: certsvp@renater.fr + =========================================================