Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2014.0599 Vulnerability in Internet Explorer Could Allow Remote Code Execution 28 April 2014 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Internet Explorer Publisher: Microsoft Operating System: Windows Impact/Access: Execute Arbitrary Code/Commands -- Remote with User Interaction Resolution: Mitigation CVE Names: CVE-2014-1776 Original Bulletin: https://technet.microsoft.com/library/security/2963983 Comment: Microsoft is aware of limited, targeted attacks that attempt to exploit a vulnerability in Internet Explorer 6, Internet Explorer 7, Internet Explorer 8, Internet Explorer 9, Internet Explorer 10, and Internet Explorer 11. - --------------------------BEGIN INCLUDED TEXT-------------------- Microsoft Security Advisory 2963983 Vulnerability in Internet Explorer Could Allow Remote Code Execution Published: April 26, 2014 Version: 1.0 General Information Executive Summary Microsoft is aware of limited, targeted attacks that attempt to exploit a vulnerability in Internet Explorer 6, Internet Explorer 7, Internet Explorer 8, Internet Explorer 9, Internet Explorer 10, and Internet Explorer 11. The vulnerability is a remote code execution vulnerability. The vulnerability exists in the way that Internet Explorer accesses an object in memory that has been deleted or has not been properly allocated. The vulnerability may corrupt memory in a way that could allow an attacker to execute arbitrary code in the context of the current user within Internet Explorer. An attacker could host a specially crafted website that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the website. On completion of this investigation, Microsoft will take the appropriate action to protect our customers, which may include providing a solution through our monthly security update release process, or an out-of-cycle security update, depending on customer needs. Mitigating Factors: * By default, Internet Explorer on Windows Server 2003, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, and Windows Server 2012 R2 runs in a restricted mode that is known as Enhanced Security Configuration. This mode mitigates this vulnerability. * By default, all supported versions of Microsoft Outlook, Microsoft Outlook Express, and Windows Mail open HTML email messages in the Restricted sites zone. The Restricted sites zone, which disables script and ActiveX controls, helps reduce the risk of an attacker being able to use this vulnerability to execute malicious code. If a user clicks a link in an email message, the user could still be vulnerable to exploitation of this vulnerability through the web-based attack scenario. * An attacker who successfully exploited this vulnerability could gain the same user rights as the current user. 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. * In a web-based attack scenario, an attacker could host a website that contains a webpage that is used to exploit this vulnerability. In addition, compromised websites and websites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these websites. Instead, an attacker would have to convince users to visit the website, typically by getting them to click a link in an email message or Instant Messenger message that takes users to the attacker's website. Issue References For more information about this issue, see the following references: References Identification CVE Reference CVE-2014-1776 Affected Software Internet Explorer 6 Internet Explorer 7 Internet Explorer 8 Internet Explorer 9 Internet Explorer 10 Internet Explorer 11 Windows Server 2003 Service Pack 2 Windows Server 2003 x64 Edition Service Pack 2 Windows Server 2003 with SP2 for Itanium-based Systems Windows Vista Service Pack 2 Windows Vista x64 Edition Service Pack 2 Windows Server 2008 for 32-bit Systems Service Pack 2 Windows Server 2008 for x64-based Systems Service Pack 2 Windows Server 2008 for Itanium-based Systems Service Pack 2 Windows 7 for 32-bit Systems Service Pack 1 Windows 7 for x64-based Systems Service Pack 1 Windows Server 2008 R2 for x64-based Systems Service Pack 1 Windows Server 2008 R2 for Itanium-based Systems Service Pack 1 Windows 8 for 32-bit Systems Windows 8 for x64-based Systems Windows Server 2012 Windows RT Windows 8.1 for 32-bit Systems Windows 8.1 for x64-based Systems Windows Server 2012 R2 Windows RT 8.1 Workarounds * Deploy the Enhanced Mitigation Experience Toolkit 4.1 The Enhanced Mitigation Experience Toolkit (EMET) helps mitigate the exploitation of this vulnerability by adding additional protection layers that make the vulnerability harder to exploit. EMET 4.1 is officially supported by Microsoft. At this time, EMET is only available in the English language. For more information, see Microsoft Knowledge Base Article 2458544. Note EMET 3.0 does not mitigate this issue. For more information about configuring EMET, see the EMET User's Guide: On 32-bit systems the EMET User's Guide is located in C:\Program Files\EMET\EMET User's Guide.pdf On 64-bit systems the EMET User's Guide is located in C:\Program Files (x86)\EMET\EMET User's Guide.pdf Configure EMET 4.1 for Internet Explorer EMET 4.1, in the recommended configuration, is automatically configured to help protect Internet Explorer. No additional steps are required. Configure EMET for Internet Explorer using Group Policy EMET can be configured using Group Policy. For information about configuring EMET using Group Policy, see the EMET User's Guide: On 32-bit systems the EMET User's Guide is located in C:\Program Files\EMET\EMET User's Guide.pdf On 64-bit systems the EMET User's Guide is located in C:\Program Files (x86)\EMET\EMET User's Guide.pdf Note For more information about Group Policy, see Group Policy collection. * Set Internet and Local intranet security zone settings to "High" to block ActiveX Controls and Active Scripting in these zones You can help protect against exploitation of this vulnerability by changing your settings for the Internet security zone to block ActiveX controls and Active Scripting. You can do this by setting your browser security to High. To raise the browsing security level in Internet Explorer, perform the following steps: 1. On the Internet Explorer Tools menu, click Internet Options. 2. In the Internet Options dialog box, click the Security tab, and then click Internet. 3. Under Security level for this zone, move the slider to High. This sets the security level for all websites you visit to High. 4. Click Local intranet. 5. Under Security level for this zone, move the slider to High. This sets the security level for all websites you visit to High. 6. Click OK to accept the changes and return to Internet Explorer. Note If no slider is visible, click Default Level, and then move the slider to High. Note Setting the level to High may cause some websites to work incorrectly. If you have difficulty using a website after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High. Impact of workaround. There are side effects to blocking ActiveX Controls and Active Scripting. Many websites that are on the Internet or on an intranet use ActiveX or Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX Controls to provide menus, ordering forms, or even account statements. Blocking ActiveX Controls or Active Scripting is a global setting that affects all Internet and intranet sites. If you do not want to block ActiveX Controls or Active Scripting for such sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone". Add sites that you trust to the Internet Explorer Trusted sites zone After you set Internet Explorer to block ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted websites exactly as you do today, while helping to protect yourself from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone. To do this, perform the following steps: 1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab. 2. In the Select a web content zone to specify its current security settings box, click Trusted Sites, and then click Sites. 3. If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box. 4. In the Add this website to the zone box, type the URL of a site that you trust, and then click Add. 5. Repeat these steps for each site that you want to add to the zone. 6. Click OK two times to accept the changes and return to Internet Explorer. Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update. * Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone You can help protect against exploitation of this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, perform the following steps: 1. In Internet Explorer, click Internet Options on the Tools menu. 2. Click the Security tab. 3. Click Internet, and then click Custom Level. 4. Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK. 5. Click Local intranet, and then click Custom Level. 6. Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK. 7. Click OK two times to return to Internet Explorer. Note Disabling Active Scripting in the Internet and Local intranet security zones may cause some websites to work incorrectly. If you have difficulty using a website after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly. Impact of workaround. There are side effects to prompting before running Active Scripting. Many websites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run Active Scripting. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone". Add sites that you trust to the Internet Explorer Trusted sites zone After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted websites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone. To do this, perform the following steps: 1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab. 2. In the Select a web content zone to specify its current security settings box, click Trusted Sites, and then click Sites. 3. If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box. 4. In the Add this website to the zone box, type the URL of a site that you trust, and then click Add. 5. Repeat these steps for each site that you want to add to the zone. 6. Click OK two times to accept the changes and return to Internet Explorer. Note Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update. * Unregister VGX.DLL 1. Click Start, click Run, type "%SystemRoot%\System32\regsvr32.exe" -u "%CommonProgramFiles%\Microsoft Shared\VGX\vgx.dll", and then click OK. 2. A dialog box appears to confirm that the un-registration process has succeeded. Click OK to close the dialog box. Impact of Workaround: Applications that render VML will no longer do so once vgx.dll has been unregistered. When a security update is available to address this issue, you should re-register vgx.dll after installing the security update. To re-register vgx.dll follow these steps: Click Start, click Run, type "%SystemRoot%\System32\regsvr32.exe" "%CommonProgramFiles%\Microsoft Shared\VGX\vgx.dll", and then click OK. A dialog box appears to confirm that the registration process has succeeded. Click OK to close the dialog box. * Modify the Access Control List on VGX.DLL to be more restrictive To modify the Access Control List (ACL) on vgx.dll to be more restrictive, follow these steps: 1. Click Start, click Run, type "cmd" (without the quotation marks), and then click OK. 2. Type the following command at a command prompt make a note of the current ACLs that are on the file (including inheritance settings) for future reference to undo this modification: cacls "%CommonProgramFiles%\Microsoft Shared\VGX\vgx.dll" 3. Type the following command at a command prompt to deny the 'everyone' group access to this file: echo y| cacls "%CommonProgramFiles%\Microsoft Shared\VGX\vgx.dll" /d everyone 4. Close Internet Explorer, and reopen it for the changes to take effect. Impact of Workaround: Applications and Web sites that render VML may no longer display or function correctly. How to undo this workaround. Before any security updates that fix this issue can be installed, this workaround must be reverted to the previous ACL configuration for vgx.dll. To revert to the previous vgx.dll ACLs follow these steps: 1. Click Start, click Run, type "cmd" (without the quotation marks), and then click OK. 2. To revert to the previous ACL configuration for vgx.dll, type the following command and replace the ACL on vgx.dll with the ACLs it previously had, which were recorded in step 2 of this workaround The command line to do so will vary depending on your environment: echo y| cacls "%CommonProgramFiles%\Microsoft Shared\VGX\vgx.dll" /g original ACLs 3. Close Internet Explorer, and reopen it for the changes to take effect. Note If this workaround is applied, software that redistributes vgx.dll may fail to install. Before this software can be installed, this workaround must be reverted to the previous ACL configuration for vgx.dll. * Enable Enhanced Protected Mode For Internet Explorer 11 and Enable 64-bit Processes for Enhanced Protected Mode Internet Explorer 11 users can help protect against exploitation of this vulnerability by changing the Advanced Security settings for Internet Explorer. You can do this by enabling Enhanced Protected Mode (EPM) settings in your browser. This security setting will protect users of Internet Explorer 11 on Windows 7 for x64-based systems, and all Windows 8 and Windows 8.1 clients. To enable EPM in Internet Explorer, perform the following steps: 1. On the Internet Explorer Tools menu, click Internet Options. 2. In the Internet Options dialog box, click the Advanced tab, and then scroll down to the Security section of the settings list. 3. Ensure the checkboxes next to Enable Enhanced Protected Mode and Enable 64-bit processes for Enhanced Protected Mode (for 64-bit systems) are selected. 4. Click OK to accept the changes and return to Internet Explorer. 5. Restart your system. - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBU12nVxLndAQH1ShLAQLDlRAArbDG1TCG783I9Av0h+jHipJtLFF3eh3E 4tHd1V/z4mrvJGtF0EeyZGCiq8oC+AkyGoqB1snn1h3bQG5Qu3QP2/MytnHDwVnc uXIU1r5i5DXFoE0Q6ZOTO9/Fh5JljfMlKy7/6MeqMgX2CEhLVeDgZU6LshcTJVTe XBk1i7Wva0WlNkUjNsRH62mju4mUCUOknna4wd6w7b6hJ1NvWELgfVqcAaOVmnWZ wxBX7efQRiGVzVlPmTO6Nl97FRtDtABUAw7L698v7NrElYlM5uNE4f/Du2deKN8D creoMa8d3mncv0AdLXBAV6+bXQLXVhcaidXZRSv6aVAlLrElaUDTxDsElF5imtKS SCBoPu+rIVUYS1IoLzTiRrG77DxOGUoaaqf8VxCh6eziXtLxV5+Etg7qeO614kke Y/+apdEl374Ubf6YtNDVlorH14oNUyXT5BcPn/L8ZoMcrhv7vFzG0tjefewRALyD z8I1nKzUvy6yhg+THZ7AyvABGxMMwIius7dRK5apoFdax4Jm4D6bxco4bGPPdzJP IkrIt9Dcea/6+GttWCtg01EkD3z+HZaAUfEsHOoBmSb5tx/8qVFzFBeGgi5m6BFt moxGxSQ1X3J9+c3Kl+XY47mW7MaGjbZwIR4LyBBflc4eN/fo8LqXHp3VUEyfHvjv I2tBexdqfPo= =B8H7 -----END PGP SIGNATURE-----