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A deny-by-default ACL is not implemented on all VVoIP endpoint (hardware and software) VLAN interface(s) on the VVoIP routing device(s) other than at the core (as defined in the VVoIP system ACL design) to properly control VVoIP endpoint access and traffic flow.


Overview

Finding ID Version Rule ID IA Controls Severity
V-19636 VVoIP 5605 (LAN) SV-21777r1_rule ECSC-1 Medium
Description
Router ACLs are required to control access and the flow of traffic to and from VVoIP system devices and their VLANs as a protection mechanism. In general, the defined ACLs are designed in a deny-by-default manner such that only the protocols and traffic that needs to reach the device or devices in the VLAN receive the packets. The ACLs filter on VLAN, IP address / subnet, protocol type, and associated standard IP port for the protocol. In general, the ACLs mentioned are egress filters (referenced the router core) on the VLAN interfaces. Additionally, the routing devices should log and alarm on inappropriate traffic. An example of this is an HTTP request sourced from the data VLAN(s) to the endpoint or media gateway VLAN(s). The primary purpose of ACL on all VVoIP VLAN interface(s) is to block traffic to/from the data VLAN interface(s). Similar restrictions are placed on a dedicated VTC VLAN interface, however, VVoIP media and signaling is permitted in the event a VTC unit needs to communicate with the UC system.
STIG Date
Voice/Video over Internet Protocol STIG 2015-01-05

Details

Check Text ( C-23964r1_chk )
Interview the IAO to obtain the required information (VVoIP system ACL Design) to determine compliance with the requirement in the next step adjusted for the actual system design.

NOTE: This requirement addresses the following VLANs at all routing devices except those at the VVoIP system core:
EI > Hardware Endpoints: multiple VLANs generally in parallel with data LAN VLANs the number of which is dependant on the size of the LAN and as required for the reduction of broadcast domains per good LAN design. For small networks there will be a minimum of one.
> Software endpoints on workstations: multiples as with hardware endpoints.

Fix Text (F-20340r1_fix)
Ensure a deny-by-default ACL is implemented on all VVoIP endpoint (hardware and software) VLAN interface(s) on the VVoIP routing devices throughout the LAN that do not support the VVoIP system core equipment directly to control traffic as follows:
> Permit Media protocols/traffic (RTP/RTCP, SRTP/SRTCP) to/from other endpoint VLAN interface(s) (VLAN/subnet(s)) wherever they intersect.
> Deny all other traffic. End the ACL with a “deny all” statement.
NOTE: All other EI traffic at this level in the network remains confined o the VLAN and is passed to the routing device that manages EI access to the VVoIP core equipment/infrastructure. The purpose of permitting media traffic to be routed between VVoIP EI VLANs at this level is to reduce the loading of the core routing device and LAN NEs in between. This also enhances QoS within the LAN itself.

This is a finding in the event an ACL is not implemented generally as defined above but which may be or is adjusted for the specific VVoIP system design and protocols used.