Title

IP-based VTC systems must not connect to ISDN lines when connected to a classified network. (Cat I impact)

Discussion

Most CODECs have a built-in IMUX such that multiple ISDN lines can terminate directly on the CODEC. ISDN lines used for VTC transport are provided by a traditional telephone switch on an unclassified network. Connecting a classified IP network to an unclassified telephone network through a VTC CODEC while in a conference could lead to disclosure of classified information to the unclassified network and unclassified VTC endpoints. While this issue might be mitigated by using a Type 1 encryptor between the CODEC and an external IMUX, an SOP would need to be in place which would dictate that the ISDN connection must be established and the Type 1 encryptor synced with the other end BEFORE the CODEC was connected to the classified IP network. This type of operation is risky and prone to error and is therefore not recommended.

Check Content

Review the VTC system architecture and inspect the VTC CODEC to verify that ISDN lines are not connected directly to the CODEC if it connects to a classified IP network (e.g., SIPRNet, JWICS) at any time. If they are, this is a finding. Note: If the VTC system is used to support multiple networks having different classification levels, and the ISDN lines are isolated from classified IP, they must meet periods processing requirements.

Fix Text

Do not simultaneously connect ISDN lines to a VTC CODEC if the CODEC connects to a classified IP network.

Additional Identifiers

Rule ID: SV-55746r2_rule

Vulnerability ID: V-43017

Group Title: RTS-VTC 7040

Expert Comments

CCIs tied to check.

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