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Unauthorized Digital Certificates Could Allow Spoofing

Unauthorized Digital Certificates Could Allow Spoofing

Published: June 03, 2012 | Updated: June 13, 2012

Version: 1.1

General Information

Executive Summary

Microsoft is aware of active attacks using unauthorized digital certificates derived from a Microsoft Certificate Authority. An unauthorized certificate could be used to spoof content, perform phishing attacks, or perform man-in-the-middle attacks. This issue affects all supported releases of Microsoft Windows.

Microsoft is providing an update for all supported releases of Microsoft Windows. The update revokes the trust of the following intermediate CA certificates:

  • Microsoft Enforced Licensing Intermediate PCA (2 certificates)
  • Microsoft Enforced Licensing Registration Authority CA (SHA1)

Recommendation. For supported releases of Microsoft Windows, Microsoft recommends that customers apply the update immediately using update management software, or by checking for updates using the Microsoft Update service. For more information, see the Suggested Actions section of this advisory.

Advisory Details

Issue References

For more information about this issue, see the following references:

ReferencesIdentification
Microsoft Knowledge Base Article2718704 

Affected Software and Devices

This advisory discusses the following affected software and devices.

Affected Software
Operating System
Windows XP Service Pack 3
Windows XP Professional x64 Edition Service Pack 2
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
Windows 7 for 32-bit Systems Service Pack 1
Windows 7 for x64-based Systems
Windows 7 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based
Windows Server 2008 R2 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for Itanium-based Systems
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1
Server Core installation option
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
Windows Server 2008 R2 for x64-based Systems (Server Core installation)
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)

 

Non-Affected Devices
Windows Mobile 6.x
Windows Phone 7
Windows Phone 7.5

Why was this advisory revised June 13, 2012? 
Microsoft revised this advisory to notify customers that after further investigation, Microsoft has determined that Windows Mobile 6.x, Windows Phone 7, and Windows Phone 7.5 devices are not affected by the issue.

What is the scope of the advisory? 
The purpose of this advisory is to notify customers that Microsoft has confirmed two unauthorized certificates have been issued by Microsoft and are being used in active attacks. During our investigation, a third Certificate Authority has been found to have issued certificates with weak ciphers.

Microsoft has issued an update for all supported releases of Microsoft Windows that addresses the issue.

Does this update address any other unauthorized digital certificates? 
Yes, in addition to addressing the three unauthorized certificates described in this advisory, this update is cumulative and addresses unauthorized digital certificates described in previous advisories: Microsoft Security Advisory 2524375, Microsoft Security Advisory 2607712, and Microsoft Security Advisory 2641690.

Is Windows 8 Consumer Preview affected by the issue addressed in this advisory?  
Yes. The update is available for the Windows 8 Consumer Preview release. Customers with Windows 8 Consumer Preview are encouraged to apply the updates to their systems. The updates are only available on Windows Update.

Is Windows 8 Release Preview affected by the issue addressed in this advisory?  
Yes. The update is available for the Windows 8 Release Preview release. Customers with Windows 8 Release Preview are encouraged to apply the updates to their systems. The updates are only available on Windows Update.

What is cryptography?
Cryptography is the science of securing information by converting it between its normal, readable state (called plaintext) and one in which the data is obscured (known as ciphertext).

In all forms of cryptography, a value known as a key is used in conjunction with a procedure called a crypto algorithm to transform plaintext data into ciphertext. In the most familiar type of cryptography, secret-key cryptography, the ciphertext is transformed back into plaintext using the same key. However, in a second type of cryptography, public-key cryptography, a different key is used to transform the ciphertext back into plaintext.

What is a digital certificate?
In public-key cryptography, one of the keys, known as the private key, must be kept secret. The other key, known as the public key, is intended to be shared with the world. However, there must be a way for the owner of the key to tell the world who the key belongs to. Digital certificates provide a way to do this. A digital certificate is a tamperproof piece of data that packages a public key together with information about it - who owns it, what it can be used for, when it expires, and so forth.

What are certificates used for?
Certificates are used primarily to verify the identity of a person or device, authenticate a service, or encrypt files. Normally you won’t have to think about certificates at all. You might, however, see a message telling you that a certificate is expired or invalid. In those cases you should follow the instructions in the message.

What is a certification authority (CA)?
Certification authorities are the organizations that issue certificates. They establish and verify the authenticity of public keys that belong to people or other certification authorities, and they verify the identity of a person or organization that asks for a certificate.

What is a Certificate Trust List (CTL)?
A trust must exist between the recipient of a signed message and the signer of the message. One method of establishing this trust is through a certificate, an electronic document verifying that entities or persons are who they claim to be. A certificate is issued to an entity by a third party that is trusted by both of the other parties. So, each recipient of a signed message decides if the issuer of the signer's certificate is trustworthy. CryptoAPI has implemented a methodology to allow application developers to create applications that automatically verify certificates against a predefined list of trusted certificates or roots. This list of trusted entities (called subjects) is called a certificate trust list (CTL). For more information, please see the MSDN article, Certificate Trust Verification.

What caused the issue?
Microsoft is aware of active attacks using unauthorized digital certificates derived from a Microsoft Certificate Authority. A unauthorized certificate could be used to spoof content, perform phishing attacks, or perform man-in-the-middle attacks. This issue affects all supported releases of Microsoft Windows.

What might an attacker use the issue to do? 
An attacker could use these certificates to spoof content, perform phishing attacks, or perform man-in-the-middle attacks.

What is a man-in-the-middle attack?
A man-in-the-middle attack occurs when an attacker reroutes communication between two users through the attacker’s computer without the knowledge of the two communicating users. Each user in the communication unknowingly sends traffic to and receives traffic from the attacker, all the while thinking they are communicating only with the intended user.

What is Microsoft doing to help with resolving this issue?
We have updated the Untrusted Certificate Store to remove the trust in the affected Microsoft certification authorities.

After applying the update, how can I verify the certificates in the Microsoft Untrusted Certificates Store? 
For information on how to view certificates, see the MSDN article, How to: View Certificates with the MMC Snap-in.

In the Certificates MMC snap-in, verify that the following certificates have been added to the Untrusted Certificates folder:

CertificateIssued byThumbprint
Microsoft Enforced Licensing Intermediate PCAMicrosoft Root Authority2a 83 e9 02 05 91 a5 5f c6 dd ad 3f b1 02 79 4c 52 b2 4e 70
Microsoft Enforced Licensing Intermediate PCAMicrosoft Root Authority3a 85 00 44 d8 a1 95 cd 40 1a 68 0c 01 2c b0 a3 b5 f8 dc 08
Microsoft Enforced Licensing Registration Authority CA (SHA1)Microsoft Root Certificate Authorityfa 66 60 a9 4a b4 5f 6a 88 c0 d7 87 4d 89 a8 63 d7 4d ee 97

For supported releases of Microsoft Windows

The majority of customers have automatic updating enabled and will not need to take any action because the KB2718704 update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.

For administrators and enterprise installations, or end users who want to install the KB2718704 update manually, Microsoft recommends that customers apply the update immediately using update management software, or by checking for updates using the Microsoft Update service. For more information on how to manually apply the update, see Microsoft Knowledge Base Article 2718704.

Additional Suggested Actions

  • Protect your PC

    We continue to encourage customers to follow our Protect Your Computer guidance of enabling a firewall, getting software updates and installing antivirus software. Customers can learn more about these steps by visiting Protect Your Computer.

    For more information about staying safe on the Internet, visit Microsoft Security Central.

  • Keep Microsoft Software Updated

    Users running Microsoft software should apply the latest Microsoft security updates to help make sure that their computers are as protected as possible. If you are not sure whether your software is up to date, visit Microsoft Update, scan your computer for available updates, and install any high-priority updates that are offered to you. If you have automatic updating enabled and configured to provide updates for Microsoft products, the updates are delivered to you when they are released, but you should verify that they are installed.

Other Information

Microsoft Active Protections Program (MAPP)

To improve security protections for customers, Microsoft provides vulnerability information to major security software providers in advance of each monthly security update release. Security software providers can then use this vulnerability information to provide updated protections to customers via their security software or devices, such as antivirus, network-based intrusion detection systems, or host-based intrusion prevention systems. To determine whether active protections are available from security software providers, please visit the active protections websites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.

Feedback

Support

  • Customers in the United States and Canada can receive technical support from Security Support. For more information about available support options, see Microsoft Help and Support.
  • International customers can receive support from their local Microsoft subsidiaries. For more information about how to contact Microsoft for international support issues, visit International Support.
  • Microsoft TechNet Security provides additional information about security in Microsoft products.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Revisions

  • V1.0 (June 3, 2012): Advisory published.
  • V1.1 (June 13, 2012): Advisory revised to notify customers that Windows Mobile 6.x, Windows Phone 7, and Windows Phone 7.5 devices are not affected by the issue.

Built at 2014-04-16T02:39:51Z-07:00

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