CVE-2016-0049 : Detail

CVE-2016-0049

6.2
/
Medium
A07-Identif. and Authent. Fail
2.55%V3
Local
2016-02-10
10h00 +00:00
2018-10-12
17h57 +00:00
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CVE Descriptions

Kerberos in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, and Windows 10 Gold and 1511 does not properly validate password changes, which allows remote attackers to bypass authentication by deploying a crafted Key Distribution Center (KDC) and then performing a sign-in action, aka "Windows Kerberos Security Feature Bypass."

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-255 Category : Credentials Management Errors
Weaknesses in this category are related to the management of credentials.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 6.2 MEDIUM CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Local

A vulnerability exploitable with Local access means that the vulnerable component is not bound to the network stack, and the attacker's path is via read/write/execute capabilities. In some cases, the attacker may be logged in locally in order to exploit the vulnerability, otherwise, she may rely on User Interaction to execute a malicious file.

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

None

There is no loss of confidentiality within the impacted component.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

None

There is no impact to availability within the impacted component.

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 [email protected]
V2 2.1 AV:L/AC:L/Au:N/C:N/I:P/A:N [email protected]

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 39442

Publication date : 2016-02-14 23h00 +00:00
Author : Nabeel Ahmed
EDB Verified : Yes

# Exploit Title: Windows Kerberos Security Feature Bypass # Date: 12-02-2016 # Exploit Author: Nabeel Ahmed # Tested on: Windows 7 Professional (x32/x64) # CVE : CVE-2016-0049 # Category: Local Exploit 1) Prerequisites: - Standard Windows 7 Fully patched and member of an existing domain. - BitLocker enabled without PIN or USB key. - Password Caching enabled - Victim has cached credentials stored on the system from previous logon. 2) Reproduce: STEP 1: Obtain physical access to a desktop or laptop with the above configuration. STEP 2: Boot system and determine FQDN of the device. (example. CLIENT.domain.local), this can be obtained by monitoring the network broadcast communication, which the system sends prior to loggin in. The username can be extracted from the loginscreen (E.g USER1) STEP 3: Create Active Directory for the domain you obtained in STEP 2 (domain.local). STEP 4: Create User with similar name as the previously logged in user. (E.g domain\USER1), and force user to change password upon next login. STEP 5: Create Computer Object in Active Directory with the same name as the target system. (E.g CLIENT) STEP 6: Use ADSI Edit and change the attribute ServicePrincipleName of the Computer Object you created in STEP 5, Add the FQDN as following (HOST/CLIENT.domain.local). STEP 7: Establish network connection between the target system and the newly created Domain Controller. STEP 8: Login with the password defined in STEP 4. STEP 9: Target system displays change password screen, set new password and confirm. STEP 10: Message "Your Password has been changed" is displayed, followed by the following error message "The trust relationship between this workstation and the primary domain failed." STEP 11: Disconnect Target system's network connection. STEP 12: Login with the new changed password. 3) Impact: Access gained to the information stored to the FDE target system without previous knowledge of password or any other information. 4) Solution: Install the latest patches from 09-02-2016 using Windows Update. 5) References: https://technet.microsoft.com/en-us/library/security/ms16-014.aspx https://support.microsoft.com/en-us/kb/3134228 6) Credits: Vulnerability discovered by Nabeel Ahmed (https://twitter.com/NabeelAhmedBE) and Tom Gilis (https://twitter.com/tgilis) of Dimension Data (https://www.dimensiondata.com)

Products Mentioned

Configuraton 0

Microsoft>>Windows_10 >> Version -

Microsoft>>Windows_10 >> Version 1511

Microsoft>>Windows_7 >> Version *

Microsoft>>Windows_8.1 >> Version *

Microsoft>>Windows_server_2008 >> Version *

Microsoft>>Windows_server_2008 >> Version r2

Microsoft>>Windows_server_2012 >> Version -

Microsoft>>Windows_server_2012 >> Version r2

Microsoft>>Windows_vista >> Version *

References

http://www.securitytracker.com/id/1034985
Tags : vdb-entry, x_refsource_SECTRACK
https://www.exploit-db.com/exploits/39442/
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.securityfocus.com/bid/82535
Tags : vdb-entry, x_refsource_BID