The network device must use its loopback or OOB management interface address as the source address when originating TFTP or FTP traffic.

From Infrastructure Router Security Technical Implementation Guide

Part of FTP/TFTP traffic does not use loopback address or OOB Management interface.

Associated with IA controls: ECSC-1

SV-15351r4_rule The network device must use its loopback or OOB management interface address as the source address when originating TFTP or FTP traffic.

Vulnerability discussion

Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of network devices. It is easier to construct appropriate ingress filters for management plane traffic destined to the network management subnet since the source addresses will be from the range used for loopback interfaces instead of a larger range of addresses used for physical interfaces. Log information recorded by authentication and syslog servers will record the router's loopback address instead of the numerous physical interface addresses. TFTP and FTP messages sent to management servers should use the loopback address as the source address.

Check content

Review the device configuration to verify the loopback interface address is used as the source address when originating TFTP or FTP traffic. If the device is managed from an OOB management network, the OOB interface must be used instead. If the loopback or OOB management interface isn't being used as the source address for TFTP or FTP traffic, this is a finding.

Fix text

Configure the network device to use a loopback or OOB management interface address as the source address when originating TFTP or FTP traffic.

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