Vulnerability Note VU#213119
Microsoft Windows Kerberos Key Distribution Center (KDC) fails to properly validate Privilege Attribute Certificate (PAC) signature
Original Release date: 18 Nov 2014 | Last revised: 19 Nov 2014

Overview
Microsoft Windows Kerberos KDC contains a vulnerability allowing an authenticated unprivileged domain user to escalate privileges to a domain administrator account, allowing the user to compromise any computer on the domain.

Description
CWE-347: Improper Verification of Cryptographic Signature
The Microsoft Windows Kerberos KDC fails to properly check for valid signatures in the Privilege Attribute Certificate (PAC) included with the Kerberos ticket request. A domain user may forge the information contained in the PAC to request higher user privileges than should be allowed. Since the KDC does not verify the signature correctly, it will award the user the requested privileges, effectively making the user a domain administrator and allowing complete compromise of the entire domain.

The Microsoft Research Security and Defense Blog has a more technical description of the vulnerability.

Impact
An unprivileged domain user may escalate to domain administrator privileges, allowing the user to fully compromise any computer on the domain, including the domain controller.

Solution
Apply an update

Microsoft has released an update addressing this vulnerability. Please see Microsoft Security Bulletin MS14-068 for more information.

Vendor Information (Learn More)

VendorStatusDate NotifiedDate UpdatedMicrosoft CorporationAffected-18 Nov 2014If you are a vendor and your product is affected, let
us know.

CVSS Metrics (Learn More)

Group
Score
Vector

Base
9.0
AV:N/AC:L/Au:S/C:C/I:C/A:C

Temporal
7.4
E:F/RL:OF/RC:C

Environmental
8.5
CDP:MH/TD:H/CR:ND/IR:ND/AR:ND

References

https://technet.microsoft.com/library/security/MS14-068
http://blogs.technet.com/b/srd/archive/2014/11/18/additional-information-about-cve-2014-6324.aspx
http://msdn.microsoft.com/en-us/library/cc237955.aspx

Credit

Microsoft credits the Qualcomm Information Security & Risk Management team, with special recognition for Tom Maddock.
This document was written by Garret Wassermann.

Other Information

CVE IDs:
CVE-2014-6324

US-CERT Alert:
TA14-323A

Date Public:
18 Nov 2014

Date First Published:
18 Nov 2014

Date Last Updated:
19 Nov 2014

Document Revision:
32

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