Information
Verify no tunnel interfaces are defined.
Rationale:
Tunnel interfaces should not exist in general. They can be used for malicious purposes. If they are necessary, the network admin's should be well aware of them and their purpose.
Solution
Remove any tunnel interfaces.
hostname(config)#no interface tunnel {instance}
Impact:
Organizations should plan and implement enterprise network security policies that disable insecure and unnecessary features that increase attack surfaces such as 'tunnel interfaces'.
Default Value:
No tunnel interfaces are defined
References:
http://www.cisco.com/en/US/docs/ios-xml/ios/interface/command/ir-i1.html#GUID-0D6BDFCD-3FBB-4D26-A274-C1221F8592DF