ID CVE-2011-0091
Summary Kerberos in Microsoft Windows Server 2008 R2 and Windows 7 does not prevent a session from changing from strong encryption to DES encryption, which allows man-in-the-middle attackers to spoof network traffic and obtain sensitive information via a DES downgrade, aka "Kerberos Spoofing Vulnerability."
References
Vulnerable Configurations
  • Microsoft Windows 7
    cpe:2.3:o:microsoft:windows_7
  • Windows Server 2008 R2 for Itanium-based Systems
    cpe:2.3:o:microsoft:windows_server_2008:r2:-:itanium
  • Windows Server 2008 R2 for 32-bit Systems
    cpe:2.3:o:microsoft:windows_server_2008:r2:-:x64
CVSS
Base: 6.4 (as of 10-02-2011 - 14:07)
Impact:
Exploitability:
CWE CWE-287
CAPEC
  • Authentication Abuse
    An attacker obtains unauthorized access to an application, service or device either through knowledge of the inherent weaknesses of an authentication mechanism, or by exploiting a flaw in the authentication scheme's implementation. In such an attack an authentication mechanism is functioning but a carefully controlled sequence of events causes the mechanism to grant access to the attacker. This attack may exploit assumptions made by the target's authentication procedures, such as assumptions regarding trust relationships or assumptions regarding the generation of secret values. This attack differs from Authentication Bypass attacks in that Authentication Abuse allows the attacker to be certified as a valid user through illegitimate means, while Authentication Bypass allows the user to access protected material without ever being certified as an authenticated user. This attack does not rely on prior sessions established by successfully authenticating users, as relied upon for the "Exploitation of Session Variables, Resource IDs and other Trusted Credentials" attack patterns.
  • Exploiting Trust in Client (aka Make the Client Invisible)
    An attack of this type exploits a programs' vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by placing themselves in the communication channel between client and server such that communication directly to the server is possible where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
  • Utilizing REST's Trust in the System Resource to Register Man in the Middle
    This attack utilizes a REST(REpresentational State Transfer)-style applications' trust in the system resources and environment to place man in the middle once SSL is terminated. Rest applications premise is that they leverage existing infrastructure to deliver web services functionality. An example of this is a Rest application that uses HTTP Get methods and receives a HTTP response with an XML document. These Rest style web services are deployed on existing infrastructure such as Apache and IIS web servers with no SOAP stack required. Unfortunately from a security standpoint, there frequently is no interoperable identity security mechanism deployed, so Rest developers often fall back to SSL to deliver security. In large data centers, SSL is typically terminated at the edge of the network - at the firewall, load balancer, or router. Once the SSL is terminated the HTTP request is in the clear (unless developers have hashed or encrypted the values, but this is rare). The attacker can utilize a sniffer such as Wireshark to snapshot the credentials, such as username and password that are passed in the clear once SSL is terminated. Once the attacker gathers these credentials, they can submit requests to the web service provider just as authorized user do. There is not typically an authentication on the client side, beyond what is passed in the request itself so once this is compromised, then this is generally sufficient to compromise the service's authentication scheme.
  • Man in the Middle Attack
    This type of attack targets the communication between two components (typically client and server). The attacker places himself in the communication channel between the two components. Whenever one component attempts to communicate with the other (data flow, authentication challenges, etc.), the data first goes to the attacker, who has the opportunity to observe or alter it, and it is then passed on to the other component as if it was never intercepted. This interposition is transparent leaving the two compromised components unaware of the potential corruption or leakage of their communications. The potential for Man-in-the-Middle attacks yields an implicit lack of trust in communication or identify between two components.
Access
VectorComplexityAuthentication
NETWORK LOW NONE
Impact
ConfidentialityIntegrityAvailability
PARTIAL PARTIAL NONE
msbulletin via4
bulletin_id MS11-013
bulletin_url
date 2011-02-08T00:00:00
impact Elevation of Privilege
knowledgebase_id 2496930
knowledgebase_url
severity Important
title Vulnerabilities in Kerberos Could Allow Elevation of Privilege
nessus via4
NASL family Windows : Microsoft Bulletins
NASL id SMB_NT_MS11-013.NASL
description The implementation of Kerberos on the remote Windows host is affected by one or more vulnerabilities : - Microsoft's Kerberos implementation uses a weak hashing mechanism, which can allow for certain aspects of a Kerberos service ticket to be forged. Note that this is not exploitable on domains where the domain controllers are running Windows Server 2008 or Windows Server 2008 R2. (CVE-2011-0043) - An attacker can force a downgrade in Kerberos communication between a client and server to a weaker encryption standard than negotiated originally by means of a man-in-the-middle attack because Windows does not correctly enforce the stronger default encryption standards included in Windows 7 and Windows Server 2008 R2. Note that this issue only affects implementations of Kerberos on Windows 7 and Windows Server 2008 R2. (CVE-2011-0091)
last seen 2019-02-21
modified 2018-11-15
plugin id 51913
published 2011-02-08
reporter Tenable
source https://www.tenable.com/plugins/index.php?view=single&id=51913
title MS11-013: Vulnerabilities in Kerberos Could Allow Elevation of Privilege (2496930)
oval via4
accepted 2012-03-26T04:01:56.958-04:00
class vulnerability
contributors
  • name Josh Turpin
    organization Symantec Corporation
  • name Josh Turpin
    organization Symantec Corporation
  • name Dragos Prisaca
    organization Symantec Corporation
definition_extensions
  • comment Microsoft Windows 7 (32-bit) is installed
    oval oval:org.mitre.oval:def:6165
  • comment Microsoft Windows 7 x64 Edition is installed
    oval oval:org.mitre.oval:def:5950
  • comment Microsoft Windows Server 2008 R2 x64 Edition is installed
    oval oval:org.mitre.oval:def:6438
  • comment Microsoft Windows Server 2008 R2 Itanium-Based Edition is installed
    oval oval:org.mitre.oval:def:5954
  • comment Microsoft Windows 7 (32-bit) Service Pack 1 Release Candidate is installed
    oval oval:org.mitre.oval:def:12295
  • comment Microsoft Windows 7 x64 Service Pack 1 Release Candidate is installed
    oval oval:org.mitre.oval:def:12435
  • comment Microsoft Windows 7 (32-bit) Service Pack 1 is installed
    oval oval:org.mitre.oval:def:12292
  • comment Microsoft Windows 7 x64 Service Pack 1 is installed
    oval oval:org.mitre.oval:def:12627
  • comment Microsoft Windows Server 2008 R2 x64 Service Pack 1 Release Candidate is installed
    oval oval:org.mitre.oval:def:11590
  • comment Microsoft Windows Server 2008 R2 Itanium-Based Edition Service Pack 1 Release Candidate is installed
    oval oval:org.mitre.oval:def:12159
  • comment Microsoft Windows Server 2008 R2 x64 Service Pack 1 is installed
    oval oval:org.mitre.oval:def:12567
  • comment Microsoft Windows Server 2008 R2 Itanium-Based Edition Service Pack 1 is installed
    oval oval:org.mitre.oval:def:12583
description Kerberos in Microsoft Windows Server 2008 R2 and Windows 7 does not prevent a session from changing from strong encryption to DES encryption, which allows man-in-the-middle attackers to spoof network traffic and obtain sensitive information via a DES downgrade, aka "Kerberos Spoofing Vulnerability."
family windows
id oval:org.mitre.oval:def:12498
status accepted
submitted 2008-01-08T14:23:12
title Kerberos Spoofing Vulnerability
version 73
refmap via4
bid 46140
confirm http://support.avaya.com/css/P8/documents/100127250
ms MS11-013
osvdb 70835
sectrack 1025048
secunia 43257
vupen ADV-2011-0326
xf ms-kerberos-spoofing(64901)
Last major update 18-07-2011 - 22:42
Published 10-02-2011 - 11:00
Last modified 30-10-2018 - 12:27
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