Microsoft Security Advisory 3046310

Improperly Issued Digital Certificates Could Allow Spoofing

Published: March 16, 2015 | Updated: March 19, 2015

Version: 2.0

Microsoft is aware of an improperly issued SSL certificate for the domain “live.fi” that could be used in attempts to spoof content, perform phishing attacks, or perform man-in-the-middle attacks. It cannot be used to issue other certificates, impersonate other domains, or sign code. This issue affects all supported releases of Microsoft Windows. Microsoft is not currently aware of attacks related to this issue.

To help protect customers from potentially fraudulent use of this digital certificate, it has been revoked by the issuing CA and Microsoft is updating the Certificate Trust list (CTL) for all supported releases of Microsoft Windows to remove the trust of certificates that are causing this issue. For more information about these certificates, see the Frequently Asked Questions section of this advisory.

Recommendation. An automatic updater of revoked certificates is included in supported editions of Windows 8, Windows 8.1, Windows RT, Windows RT 8.1, Windows Server 2012, and Windows Server 2012 R2, and for devices running Windows Phone 8 and Windows Phone 8.1. For these operating systems and devices, customers do not need to take any action as these systems and devices will be automatically protected.

For systems running Windows Vista, Windows 7, Windows Server 2008, or Windows Server 2008 R2 that are using the automatic updater of revoked certificates (see Microsoft Knowledge Base Article 2677070 for details), customers do not need to take any action as these systems will be automatically protected.

For customers running Windows Server 2003 Microsoft recommends that the 3046310 update be applied immediately using update management software, by checking for updates using the Microsoft Update service, or by downloading and applying the update manually. For more information, see the Suggested Actions section of this advisory.

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

References

Identification

Microsoft Knowledge Base Article

3046310

This advisory discusses the following software.

Affected Software

Operating System

Windows Server 2003 Service Pack 2 (Available March 19)

Windows Server 2003 x64 Edition Service Pack 2 (Available March 19)

Windows Server 2003 with SP2 for Itanium-based Systems (Available March 19)

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 8.1 for 32-bit Systems

Windows 8.1 for x64-based Systems

Windows RT

Windows RT 8.1

Windows Server 2012

Windows Server 2012 R2

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 2012 (Server Core installation)

Windows Server 2012 R2 (Server Core installation)

Affected Devices

Windows Phone 8

Windows Phone 8.1

What is the scope of the advisory? 
The purpose of this advisory is to notify customers that an SSL digital certificate was improperly issued. This SSL certificate could be used to spoof content, perform phishing attacks, or perform man-in-the-middle attacks against several Microsoft web properties. It cannot be used to issue other certificates, impersonate other domains, or sign code.

What caused the issue? 
A certificate was improperly issued due to a misconfigured privileged email account on the live.fi domain. An email account was able to be registered for the live.fi domain using a privileged username, which was subsequently used to request an unauthorized certificate for that domain.

Does this update address any other digital certificates? 
Yes, in addition to addressing the certificates described in this advisory, this update is cumulative and includes digital certificates described in previous advisories:

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 might an attacker do with these certificates? 
An attacker could use these certificates to spoof content, perform phishing attacks, or perform man-in-the-middle attacks against the following web properties:

  • live.fi
  • www.live.fi

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?  
Although this issue does not result from an issue in any Microsoft product, we are nevertheless updating the CTL and providing an update to help protect customers. Microsoft will continue to investigate this issue and may make future changes to the CTL or release a future update to help protect customers.

After applying the update, how can I verify the certificates in the Microsoft Untrusted Certificates Store? 
For Windows Vista, Windows 7, Windows Server 2008, and Windows Server 2008 R2 systems that are using the automatic updater of revoked certificates (see Microsoft Knowledge Base Article 2677070 for details), and for Windows 8, Windows 8.1, Windows RT, Windows RT 8.1, Windows Server 2012, and Windows Server 2012 R2 systems, you can check the Application log in the Event Viewer for an entry with the following values:

  • Source: CAPI2
  • Level: Information
  • Event ID: 4112
  • Description: Successful auto update of disallowed certificate list with effective date: Friday, March 13, 2015 (or later).

For systems not using the automatic updater of revoked certificates, in the Certificates MMC snap-in, verify that the following certificate has been added to the Untrusted Certificates folder:

Certificate

Issued by

Thumbprint

www.live.fi

COMODO RSA Domain Validation Secure Server CA

‎08 e4 98 72 49 bc 45 07 48 a4 a7 81 33 cb f0 41 a3 51 00 33

Note For information on how to view certificates with the MMC Snap-in, see the MSDN article, How to: View Certificates with the MMC Snap-in.

Apply the update for supported releases of Microsoft Windows

An automatic updater of revoked certificates is included in supported editions of Windows 8, Windows 8.1, Windows RT, Windows RT 8.1, Windows Server 2012, and Windows Server 2012 R2, and for devices running Windows Phone 8 and Windows Phone 8.1. For these operating systems or devices, customers do not need to take any action because the CTL will be updated automatically.

For systems running Windows Vista, Windows 7, Windows Server 2008, or Windows Server 2008 R2 that are using the automatic updater of revoked certificates (see Microsoft Knowledge Base Article 2677070 for details), customers do not need to take any action because the CTL will be updated automatically.

For customers running Windows Server 2003, or for customers who choose not to install the automatic updater of revoked certificates, Microsoft recommends that the 3046310 update be applied immediately using update management software, by checking for updates using the Microsoft Update service, or by downloading and applying the update manually. See Microsoft Knowledge Base Article 3046310 for download links.

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. For more information, see Microsoft Safety & Security Center.

  • 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.

Feedback

Support

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 (March 16, 2015): Advisory published.
  • V2.0 (March 19, 2015): Advisory rereleased to announce that the update for supported editions of Windows Server 2003 is now available. See Knowledge Base Article 3046310 for more information and download links.

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