Disable: 'Domain member: Digitally sign secure channel data (when possible)' for signsecurechannel This policy setting determines whether a domain member should attempt to negotiate whether all secure channel traffic that it initiates must be digitally signed. Digital signatures protect the traffic from being modified by anyone who captures the data as it traverses the network. Microsoft recommends to configure the Domain member: Digitally sign secure channel data (when possible) setting to Enabled. Counter Measure: * Enable the Domain member: Digitally encrypt or sign secure channel data (always) setting. * Enable the Domain member: Digitally encrypt secure channel data (when possible) setting. * Enable the Domain member: Digitally sign secure channel data (when possible) setting. Potential Impact: Digital encryption and signing of the "secure channel" is a good idea where it is supported. The secure channel protects domain credentials as they are sent to the domain controller. However, only Windows NT 4.0 with Service Pack 6a (SP6a) and subsequent versions of the Windows operating system support digital encryption and signing of the secure channel. Windows 98 Second Edition clients do not support it unless they have the Dsclient installed. Therefore, you cannot enable the Domain member: Digitally encrypt or sign secure channel data (always) setting on domain controllers that support Windows 98 clients as members of the domain. Potential impacts can include the following: * The ability to create or delete trust relationships with clients running versions of Windows earlier than Windows NT 4.0 with SP6a will be disabled. * Logons from clients running versions of Windows earlier than Windows NT 4.0 with SP6a will be disabled. * The ability to authenticate other domains' users from a domain controller running a version of Windows earlier than Windows NT 4.0 with SP6a in a trusted domain will be disabled. You can enable this policy setting after you eliminate all Windows 9x clients from the domain and upgrade all Windows NT 4.0 servers and domain controllers from trusted/trusting domains to Windows NT 4.0 with SP6a. You can enable the other two policy settings, Domain member: Digitally encrypt secure channel data (when possible) and Domain member: Digitally encrypt sign channel data (when possible), on all computers in the domain that support them and clients running versions of Windows earlier than Windows NT 4.0 with SP6a and applications that run on these versions of Windows will not be affected." [enable/disable] (1) GPO: Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\Domain member: Digitally sign secure channel data (when possible) (2) REG: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Netlogon\Parameters\signsecurechannel oval:org.secpod.oval:def:35022 SCAP Repo OVAL Definition 2016-06-10