# CVE-2017-8495: Kerberos SNAME Security Feature Bypass Vulnerability

CVE-2017-8495 is fixed in 27 products on 1 platform, first by KB4025344, released July 11, 2017. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2017-8495
- Priority: High
- CVSS: 7.5 (Important)
- EPSS: 0.0462
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 11, 2017
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2017-8495

## Description

<p>A security feature bypass vulnerability exists in Microsoft Windows when Kerberos fails to prevent tampering with the SNAME field during ticket exchange. An attacker who successfully exploited this vulnerability could use it to bypass Extended Protection for Authentication.</p> <p>To exploit this vulnerability, an attacker would have to be able to launch a man-in-the-middle (<a href="https://technet.microsoft.com/en-us/library/security/dn848375.aspx#MiTM">MiTM</a>) attack against the traffic passing between a client and the server.</p> <p>The update addresses this vulnerability by adding integrity protection to the SNAME field.</p>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Microsoft | Windows 10 Version 1511 for 32-bit Systems | 10586.1007 | [KB4025344](https://patchblox.com/security/data/fix/microsoft/kb4025344.md) | Jul 11, 2017 |
| Microsoft | Windows 10 Version 1511 for x64-based Systems | 10586.1007 | [KB4025344](https://patchblox.com/security/data/fix/microsoft/kb4025344.md) | Jul 11, 2017 |
| Microsoft | Windows 10 Version 1607 for 32-bit Systems | 14393.1480 | [KB4025339](https://patchblox.com/security/data/fix/microsoft/kb4025339.md) | Jul 11, 2017 |
| Microsoft | Windows 10 Version 1607 for x64-based Systems | 14393.1480 | [KB4025339](https://patchblox.com/security/data/fix/microsoft/kb4025339.md) | Jul 11, 2017 |
| Microsoft | Windows 10 Version 1703 for 32-bit Systems | 15063.483 | [KB4025342](https://patchblox.com/security/data/fix/microsoft/kb4025342.md) | Jul 11, 2017 |
| Microsoft | Windows 10 Version 1703 for x64-based Systems | 15063.483 | [KB4025342](https://patchblox.com/security/data/fix/microsoft/kb4025342.md) | Jul 11, 2017 |
| Microsoft | Windows 10 for 32-bit Systems | 10240.17488 | [KB4025338](https://patchblox.com/security/data/fix/microsoft/kb4025338.md) | Jul 11, 2017 |
| Microsoft | Windows 10 for x64-based Systems | 10240.17488 | [KB4025338](https://patchblox.com/security/data/fix/microsoft/kb4025338.md) | Jul 11, 2017 |
| Microsoft | Windows 7 for 32-bit Systems Service Pack 1 |  | [KB4025341](https://patchblox.com/security/data/fix/microsoft/kb4025341.md) | Jul 11, 2017 |
| Microsoft | Windows 7 for 32-bit Systems Service Pack 1 |  | [KB4025337](https://patchblox.com/security/data/fix/microsoft/kb4025337.md) | Jul 11, 2017 |
| Microsoft | Windows 7 for x64-based Systems Service Pack 1 |  | [KB4025341](https://patchblox.com/security/data/fix/microsoft/kb4025341.md) | Jul 11, 2017 |
| Microsoft | Windows 7 for x64-based Systems Service Pack 1 |  | [KB4025337](https://patchblox.com/security/data/fix/microsoft/kb4025337.md) | Jul 11, 2017 |
| Microsoft | Windows 8.1 for 32-bit systems |  | [KB4025333](https://patchblox.com/security/data/fix/microsoft/kb4025333.md) | Jul 11, 2017 |
| Microsoft | Windows 8.1 for 32-bit systems |  | [KB4025336](https://patchblox.com/security/data/fix/microsoft/kb4025336.md) | Jul 11, 2017 |
| Microsoft | Windows 8.1 for x64-based systems |  | [KB4025333](https://patchblox.com/security/data/fix/microsoft/kb4025333.md) | Jul 11, 2017 |
| Microsoft | Windows 8.1 for x64-based systems |  | [KB4025336](https://patchblox.com/security/data/fix/microsoft/kb4025336.md) | Jul 11, 2017 |
| Microsoft | Windows RT 8.1 |  | [KB4025336](https://patchblox.com/security/data/fix/microsoft/kb4025336.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1 |  | [KB4025341](https://patchblox.com/security/data/fix/microsoft/kb4025341.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1 |  | [KB4025337](https://patchblox.com/security/data/fix/microsoft/kb4025337.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 R2 for x64-based Systems Service Pack 1 |  | [KB4025341](https://patchblox.com/security/data/fix/microsoft/kb4025341.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 R2 for x64-based Systems Service Pack 1 |  | [KB4025337](https://patchblox.com/security/data/fix/microsoft/kb4025337.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) |  | [KB4025341](https://patchblox.com/security/data/fix/microsoft/kb4025341.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) |  | [KB4025337](https://patchblox.com/security/data/fix/microsoft/kb4025337.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 for 32-bit Systems Service Pack 2 |  | [KB4022746](https://patchblox.com/security/data/fix/microsoft/kb4022746.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) |  | [KB4022746](https://patchblox.com/security/data/fix/microsoft/kb4022746.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 for Itanium-Based Systems Service Pack 2 |  | [KB4022746](https://patchblox.com/security/data/fix/microsoft/kb4022746.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 for x64-based Systems Service Pack 2 |  | [KB4022746](https://patchblox.com/security/data/fix/microsoft/kb4022746.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) |  | [KB4022746](https://patchblox.com/security/data/fix/microsoft/kb4022746.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2012 |  | [KB4025343](https://patchblox.com/security/data/fix/microsoft/kb4025343.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2012 |  | [KB4025331](https://patchblox.com/security/data/fix/microsoft/kb4025331.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2012 (Server Core installation) |  | [KB4025343](https://patchblox.com/security/data/fix/microsoft/kb4025343.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2012 (Server Core installation) |  | [KB4025331](https://patchblox.com/security/data/fix/microsoft/kb4025331.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2012 R2 |  | [KB4025333](https://patchblox.com/security/data/fix/microsoft/kb4025333.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2012 R2 |  | [KB4025336](https://patchblox.com/security/data/fix/microsoft/kb4025336.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2012 R2 (Server Core installation) |  | [KB4025333](https://patchblox.com/security/data/fix/microsoft/kb4025333.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2012 R2 (Server Core installation) |  | [KB4025336](https://patchblox.com/security/data/fix/microsoft/kb4025336.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2016 | 14393.1480 | [KB4025339](https://patchblox.com/security/data/fix/microsoft/kb4025339.md) | Jul 11, 2017 |
| Microsoft | Windows Server 2016 (Server Core installation) | 14393.1480 | [KB4025339](https://patchblox.com/security/data/fix/microsoft/kb4025339.md) | Jul 11, 2017 |

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