The Juniper EX switch must be configured to terminate all sessions and network connections when nonlocal device maintenance is completed.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-253912	JUEX-NM-000350	SV-253912r843769_rule		Medium

Description
If a device management session or connection remains open after management is completed, it may be hijacked by an attacker and used to compromise or damage the network device. Nonlocal device management and diagnostic activities are those activities conducted by individuals communicating through a network, either an external network (e.g., the internet) or an internal network. In the event the remote node has abnormally terminated or an upstream link from the managed device is down, the management session will be terminated, thereby freeing device resources and eliminating any possibility of an unauthorized user being orphaned to an open idle session of the managed device.

Description

If a device management session or connection remains open after management is completed, it may be hijacked by an attacker and used to compromise or damage the network device. Nonlocal device management and diagnostic activities are those activities conducted by individuals communicating through a network, either an external network (e.g., the internet) or an internal network. In the event the remote node has abnormally terminated or an upstream link from the managed device is down, the management session will be terminated, thereby freeing device resources and eliminating any possibility of an unauthorized user being orphaned to an open idle session of the managed device.

STIG	Date
Juniper EX Series Switches Network Device Management Security Technical Implementation Guide	2022-08-31

Details

Check Text ( C-57364r843767_chk )
Determine if the network device terminates all sessions and network connections when nonlocal device maintenance is completed. This requirement may be verified by demonstration or validated test results. Junos permits the administrator to log out after completing nonlocal maintenance, which terminates the session and the network connection. Junos forcibly terminates the session and network connection if the idle-timeout value expires or when the permissible number of missed keepalive messages is reached. Verify the number of keepalive messages and the interval between messages is appropriate. For example, to forcibly disconnect a session after 30 seconds of lost connectivity: [edit system services ssh] : client-alive-count-max 3; client-alive-interval 10; Note: Administrator inactivity timeouts not shown because these are a separate check. If the network device does not terminate all sessions and network connections when nonlocal device maintenance is complete, this is a finding.

Check Text ( C-57364r843767_chk )

Determine if the network device terminates all sessions and network connections when nonlocal device maintenance is completed. This requirement may be verified by demonstration or validated test results.

Junos permits the administrator to log out after completing nonlocal maintenance, which terminates the session and the network connection. Junos forcibly terminates the session and network connection if the idle-timeout value expires or when the permissible number of missed keepalive messages is reached. Verify the number of keepalive messages and the interval between messages is appropriate. For example, to forcibly disconnect a session after 30 seconds of lost connectivity:

[edit system services ssh]
:
client-alive-count-max 3;
client-alive-interval 10;
Note: Administrator inactivity timeouts not shown because these are a separate check.

If the network device does not terminate all sessions and network connections when nonlocal device maintenance is complete, this is a finding.

Fix Text (F-57315r843768_fix)
Configure the network device to terminate all sessions and network connections when nonlocal device maintenance is completed. set system services ssh client-alive-count-max <0..255> set system services ssh client-alive-interval <0..65535 seconds>