This security update resolves a vulnerability in Microsoft Windows. The vulnerability could allow security feature bypass if an attacker logs on to a target system and runs a specially crafted application.
This security update is rated Important for all supported editions of Windows 8.1, Windows Server 2012, Windows Server 2012 R2, Windows RT 8.1, and Windows 10. For more information, see the Affected Software section.
The security update addresses the vulnerability by correcting how Windows manages process tokens in memory. For more information about the vulnerability, see the Vulnerability Information section.
Affected Software and Vulnerability Severity Ratings
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.
The severity ratings indicated for each affected software 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 April bulletin summary.
[2]Windows 10 updates are cumulative. The monthly security release includes all security fixes for vulnerabilities that affect Windows 10, in addition to non-security updates. The updates are available via the Microsoft Update Catalog.
*The Updates Replaced column shows only the latest update in any chain of superseded updates.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).
Note Windows Server 2016 Technical Preview 4 and Windows Server 2016 Technical Preview 5 are affected. Customers running these operating systems are encouraged to apply the update, which is available via Windows Update.
Vulnerability Information
Windows CSRSS Security Feature Bypass Vulnerability - CVE-2016-0151
A security feature bypass vulnerability exists in Microsoft Windows when the Client-Server Run-time Subsystem (CSRSS) fails to properly manage process tokens in memory.
An attacker who successfully exploited this vulnerability could run arbitrary code as an administrator. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system. The security update addresses the vulnerability by correcting how Windows manages process tokens in memory.
The following table contains a link to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:
Vulnerability Title
CVE number
Publicly disclosed
Exploited
Windows CSRSS Security Feature Bypass Vulnerability
Microsoft has not identified any mitigating factors for this vulnerability.
Workarounds
Microsoft has not identified any workarounds for this vulnerability.
Security Update Deployment
For Security Update Deployment information, see the Microsoft Knowledge Base article referenced in the Executive Summary.
Acknowledgments
Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgments for more information.
Disclaimer
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.
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