Kerberos Security Feature Bypass Vulnerability



Published: 2016-09-02
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2016-3237
CWE-ID CWE-255
Exploitation vector Local network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software
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Windows
Operating systems & Components / Operating system

Windows Server
Operating systems & Components / Operating system

Vendor Microsoft

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Kerberos privilege escalation

EUVDB-ID: #VU293

Risk: Medium

CVSSv3.1: 5 [CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C]

CVE-ID: CVE-2016-3237

CWE-ID: CWE-255 - Credentials Management

Exploit availability: Yes

Description

The vulnerability allows an attacker with access to local network to gain elevated privileges.

The vulnerability exists in Kerberos implementation when handling password change request. A local attacker can make the operating system to fall back to NT LAN Manager (NTLM) Authentication Protocol as the default authentication protocol.

Successful exploitation of this vulnerability will allow a local attacker to launch a man-in-the-middle (MiTM) attack against the traffic passing between a domain controller and the target machine, intercept and decrypt credentials during password change request.

Mitigation

Install updates from Microsoft website.

Vulnerable software versions

Windows: 7 - Vista

Windows Server: 2008 - 2012 R2

External links

http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2016-3237


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.



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