Store passwords using reversible encryption

Updated: May 2, 2012

Applies To: Windows 7, Windows 8, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Vista

This security policy reference topic for the IT professional describes the best practices, location, values, and security considerations for this policy setting.

Reference

The Store password using reversible encryption policy setting provides support for applications that use protocols that require the user's password for authentication. Storing encrypted passwords in a way that is reversible means that the encrypted passwords can be decrypted. A knowledgeable attacker who is able to break this encryption can then log on to network resources by using the compromised account. For this reason, never enable Store password using reversible encryption for all users in the domain unless application requirements outweigh the need to protect password information.

If you use the Challenge Handshake Authentication Protocol (CHAP) through remote access or Internet Authentication Services (IAS), you must enable this policy setting. CHAP is an authentication protocol that is used by remote access and network connections. Digest Authentication in Internet Information Services (IIS) also requires that you enable this policy setting.

Possible values

• Enabled

• Disabled

• Not defined

Best practices

Set the value for Store password using reversible encryption to Disabled. If you use CHAP through remote access or IAS, or Digest Authentication in IIS, you must set this value to Enabled. This presents a security risk when you apply the setting by using Group Policy on a user-by-user basis because it requires opening the appropriate user account object in Active Directory Users and Computers.

Note

Do not enable this policy setting unless business requirements outweigh the need to protect password information.

Location

GPO_name**\Computer Configuration\Windows Settings\Security Settings\Account Policies\Password Policy\**

Default values

Server type or Group Policy Object (GPO)	Default value
Default domain policy	Disabled
Default domain controller policy	Disabled
Stand-alone server default settings	Disabled
Domain controller effective default settings	Disabled
Member server effective default settings	Disabled
Effective GPO default settings on client computers	Disabled

Operating system version differences

This policy setting has not changed since Windows Server 2003 and Windows XP.

Security considerations

This section describes how an attacker might exploit a feature or its configuration, how to implement the countermeasure, and the possible negative consequences of countermeasure implementation.

Vulnerability

Enabling this policy setting allows the operating system to store passwords in a format that can weaken your overall security.

Countermeasure

Disable the Store password using reversible encryption policy setting.

Potential impact

If your organization uses CHAP through remote access or IAS, or Digest Authentication in IIS, you must configure this policy setting to Enabled. This presents a security risk when you apply the setting through Group Policy on a user-by-user basis because it requires the appropriate user account object to be opened in Active Directory Users and Computers.