Title: Microsoft Windows NT/2000/XP LAN Manager Password Hashing Weakness
Severity: MODERATE
Description:
Default installations of Microsoft Windows NT, 2000, and XP systems provide support for LAN Manager (LANMAN) passwords. This is to ensure backwards compatibility with existing systems.
The algorithm used to encrypt LANMAN passwords is inherently weak. This is due to the fact that all passwords are 14 characters in length and are in upper case letters. Longer passwords are truncated and shorter passwords are padded with spaces to reach the 14 character limit. Furthermore, passwords are broken into two 7-character blocks prior to encryption.
This is of considerable concern to users of systems that provide legacy support as the LANMAN passwords may be easily guessed or brute-forced in a relatively short period of time.
This weakness has been known to affect default installations of Microsoft Windows NT, 2000 and XP systems.
Affected Products:
- Avaya DefinityOne Media Servers
- Avaya IP600 Media Servers
- Avaya S3400 Message Application Server
- Avaya S8100 Media Servers
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Advanced Server SP1
- Microsoft Windows 2000 Advanced Server SP2
- Microsoft Windows 2000 Advanced Server SP3
- Microsoft Windows 2000 Datacenter Server
- Microsoft Windows 2000 Datacenter Server SP1
- Microsoft Windows 2000 Datacenter Server SP2
- Microsoft Windows 2000 Datacenter Server SP3
- Microsoft Windows 2000 Professional
- Microsoft Windows 2000 Professional SP1
- Microsoft Windows 2000 Professional SP2
- Microsoft Windows 2000 Professional SP3
- Microsoft Windows 2000 Server
- Microsoft Windows 2000 Server SP1
- Microsoft Windows 2000 Server SP2
- Microsoft Windows 2000 Server SP3
- Microsoft Windows NT Enterprise Server 4.0
- Microsoft Windows NT Enterprise Server 4.0 SP1
- Microsoft Windows NT Enterprise Server 4.0 SP2
- Microsoft Windows NT Enterprise Server 4.0 SP3
- Microsoft Windows NT Enterprise Server 4.0 SP4
- Microsoft Windows NT Enterprise Server 4.0 SP5
- Microsoft Windows NT Enterprise Server 4.0 SP6
- Microsoft Windows NT Enterprise Server 4.0 SP6a
- Microsoft Windows NT Server 4.0
- Microsoft Windows NT Server 4.0 SP1
- Microsoft Windows NT Server 4.0 SP2
- Microsoft Windows NT Server 4.0 SP3
- Microsoft Windows NT Server 4.0 SP4
- Microsoft Windows NT Server 4.0 SP5
- Microsoft Windows NT Server 4.0 SP6
- Microsoft Windows NT Server 4.0 SP6a
- Microsoft Windows NT Terminal Server 4.0
- Microsoft Windows NT Terminal Server 4.0 SP1
- Microsoft Windows NT Terminal Server 4.0 SP2
- Microsoft Windows NT Terminal Server 4.0 SP3
- Microsoft Windows NT Terminal Server 4.0 SP4
- Microsoft Windows NT Terminal Server 4.0 SP5
- Microsoft Windows NT Terminal Server 4.0 SP6
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Workstation 4.0 SP1
- Microsoft Windows NT Workstation 4.0 SP2
- Microsoft Windows NT Workstation 4.0 SP3
- Microsoft Windows NT Workstation 4.0 SP4
- Microsoft Windows NT Workstation 4.0 SP5
- Microsoft Windows NT Workstation 4.0 SP6
- Microsoft Windows NT Workstation 4.0 SP6a
- Microsoft Windows XP Home
- Microsoft Windows XP Home SP1
- Microsoft Windows XP Professional
- Microsoft Windows XP Professional SP1
References:
- Microsoft: Q147706: How to Disable LM Authentication on Windows NT
- Microsoft: Q239869: How to Enable NTLM 2 Authentication for Windows 95/98/2000 and NT
- Microsoft: Q299656: New Registry Key to Remove LM Hashes from Active Directory and Security
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