Title

The Mapper I/O network protocol (LLTDIO) driver must be disabled. (Cat II impact)

Discussion

The Mapper I/O network protocol (LLTDIO) driver allows the discovery of the connected network and allows various options to be enabled. Disabling this helps protect the system from potentially discovering and connecting to unauthorized devices.

Check Content

If the following registry values do not exist or are not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \Software\Policies\Microsoft\Windows\LLTD\ Value Name: AllowLLTDIOOndomain Value Name: AllowLLTDIOOnPublicNet Value Name: EnableLLTDIO Value Name: ProhibitLLTDIOOnPrivateNet Type: REG_DWORD Value: 0

Fix Text

Configure the policy value for Computer Configuration -> Administrative Templates -> Network -> Link-Layer Topology Discovery -> "Turn on Mapper I/O (LLTDIO) driver" to "Disabled".

Additional Identifiers

Rule ID: SV-226135r794411_rule

Vulnerability ID: V-226135

Group Title: SRG-OS-000095-GPOS-00049

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.