Information
If the XNM-SSL service is configured, connection limits should be set.
Rationale:
JUNOScript can be configured to use SSL transport to prevent the exposure of sensitive data and authentication details on the network. If configured the XNM-SSL service will provide services on port TCP/3220.
An attacker may attempt to open a large number of sessions to the XNM-SSL service to exhaust the routers resources or an authorized user may do so accidently, especially given that the service is designed to allow a scripting and automation interface to JUNOS. To limit the impact of any such incident, the number of concurrent connections to the XNM-SSL service should explicitly limited.
A relatively low value of 10 is recommended, but may not be appropriate for all environments so it is left to the administrator's discretion.
Impact:
If the connection limit has been reached, additional JUNOScript sessions will be rejected until an existing session has ended.
Solution
The XNM-SSL Connection Limit can be configured by issuing the following command from the [edit system services xnm-ssl] hierarchy;
[edit system services xnm-ssl]
user@host#set connection-limit <limit>
Where <limit> is the permitted number of concurrent connections required.
Default Value:
The XNM-SSL Service is disabled by default.
When it is first configured the default Connection Limit is 75.