Microsoft Security Bulletin MS16-010 - Important
Security Update in Microsoft Exchange Server to Address Spoofing (3124557)
Published: January 12, 2016
This security update resolves vulnerabilities in Microsoft Exchange Server. The most severe of the vulnerabilities could allow spoofing if Outlook Web Access (OWA) fails to properly handle web requests, and sanitize user input and email content.
This security update is rated Important for all supported editions of Microsoft Exchange Server 2013 and Microsoft Exchange Server 2016. For more information, see the Affected Software section.
The security update addresses the vulnerabilities by correcting how Microsoft Exchange OWA validates web requests and by helping to ensure that OWA properly sanitizes user input and email content. For more information about the vulnerabilities, see the Vulnerability Information section.
For more information about this update, see Microsoft Knowledge Base Article 3124557.
The following software versions or editions are affected. Versions or editions that are not listed are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, see Microsoft Support Lifecycle.
|Software||Maximum Security Impact||Aggregate Severity Rating||Updates Replaced*|
|Microsoft Server Software|
|Microsoft Exchange Server 2013 Service Pack 1 (3124557)||Spoofing||Important||3087126 in MS15-103|
|Microsoft Exchange Server 2013 Cumulative Update 10 (3124557)||Spoofing||Important||None|
|Microsoft Exchange Server 2013 Cumulative Update 11 (3124557)||Spoofing||Important||None|
|Microsoft Exchange Server 2016 (3124557)||Spoofing||Important||None|
*The Updates Replaced column shows only the latest update in any chain of superseded updates. For a comprehensive list of updates replaced, go to the Microsoft Update Catalog, search for the update KB number, and then view update details (updates replaced information is provided on the Package Details tab).
Severity Ratings and Vulnerability Identifiers
The following severity ratings assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin's release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the January bulletin summary.
|Vulnerability Severity Rating and Maximum Security Impact by Affected Software|
|Affected Software||Exchange Spoofing Vulnerability - CVE-2016-0029||Exchange Spoofing Vulnerability - CVE-2016-0030||Exchange Spoofing Vulnerability - CVE-2016-0031||Exchange Spoofing Vulnerability - CVE-2016-0032||Aggregate Severity Rating|
|Microsoft Server Software|
|Microsoft Exchange Server 2013 Service Pack 1 (3124557)||Not applicable||Important Spoofing||Not applicable||Important Spoofing||Important|
|Microsoft Exchange Server 2013 Cumulative Update 10 (3124557)||Not applicable||Important Spoofing||Not applicable||Important Spoofing||Important|
|Microsoft Exchange Server 2013 Cumulative Update 11 (3124557)||Not applicable||Not applicable||Not applicable||Important Spoofing||Important|
|Microsoft Exchange Server 2016 (3124557)||Important Spoofing||Important Spoofing||Important Spoofing||Important Spoofing||Important|
Multiple Exchange Spoofing Vulnerabilities
Multiple spoofing vulnerabilities exist in Microsoft Exchange Server when Outlook Web Access (OWA) fails to properly handle web requests. An attacker who successfully exploited the vulnerabilities could perform script or content injection attacks, and attempt to trick the user into disclosing sensitive information. An attacker could also redirect the user to a malicious website that could spoof content or be used as a pivot to chain an attack with other vulnerabilities in web services.
To exploit the vulnerabilities, an attacker could send a specially crafted email containing a malicious link to a user. An attacker could also use a chat client to social engineer a user into clicking the malicious link. However, in both examples the user must click the malicious link. The security update addresses the vulnerabilities by correcting how OWA validates web requests.
The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:
|Vulnerability title||CVE number||Publicly disclosed||Exploited|
|Exchange Spoofing Vulnerability||CVE-2016-0029||No||No|
|Exchange Spoofing Vulnerability||CVE-2016-0030||No||No|
|Exchange Spoofing Vulnerability||CVE-2016-0031||No||No|
|Exchange Spoofing Vulnerability||CVE-2016-0032||No||No|
The following mitigating factors may be helpful in your situation:
- To generate the malicious link, an attacker must already be an authenticated Microsoft Exchange user and be able to send email messages.
- The malicious link could be sent in an email, but the attacker would have to convince a user to open the link in order to exploit the vulnerability.
Microsoft has not identified any workarounds for this vulnerability.
Security Update Deployment
For Security Update Deployment information, see the Microsoft Knowledge Base article referenced here in the Executive Summary.
Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgments for more information.
The information provided in the Microsoft Knowledge Base 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.
- V1.0 (January 12, 2015): Bulletin published.
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