Microsoft Windows LM / NTLMv1 Authentication Enabled

medium Nessus Plugin ID 63478

Synopsis

The remote Windows host is configured to use an insecure authentication protocol.

Description

The remote host is configured to attempt LM and/or NTLMv1 for outbound authentication. These protocols use weak encryption. A remote attacker who is able to read LM or NTLMv1 challenge and response packets could exploit this to get a user's LM or NTLM hash, which would allow an attacker to authenticate as that user.

Solution

Change the LmCompatibilityLevel setting to 3 or higher.

See Also

http://www.nessus.org/u?593e5d9d

https://support.microsoft.com/en-us/help/2793313/security-guidance-for-ntlmv1-and-lm-network-authentication

http://technet.microsoft.com/en-us/library/cc960646.aspx

Plugin Details

Severity: Medium

ID: 63478

File Name: smb_lm_ntlm_auth.nasl

Version: 1.2

Type: local

Agent: windows

Family: Windows

Published: 1/11/2013

Updated: 11/15/2018

Supported Sensors: Nessus Agent, Nessus

Risk Information

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P

Vulnerability Information

CPE: cpe:/o:microsoft:windows

Required KB Items: SMB/WindowsVersion, SMB/registry_full_access

Vulnerability Publication Date: 1/8/2013