6.10.3.3 Ensure XNM-SSL Rate Limit is Set

Information

If the XNM-SSL service is configured, the Rate Limit 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 interface to JUNOS.
To limit the impact of any such incident, the rate at which new connections to the XNM-SSL service should explicitly limited. Rate Limits are set in terms of the number of connection attempts per minute. Established connections do not count towards this count. A relatively low value of 60 (the equivalent of one attempt per second, sustained over a minute) is recommended, but may not be appropriate for all environments so it is left to the administrator's discretion.

Solution

The XNM-SSL Rate 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 rate-limit <limit>
Where <limit> is the desired Rate Limit measured in Connection Attempts per Minute.

Impact:
If the Rate Limit is exceeded, new connection attempts will be rejected until the new connection rate drops below the configured limit.

Default Value:
The XNM-SSL Service is disabled by default. When it is first configured the default Rate Limit is 150 connection attempts per second.

See Also

https://workbench.cisecurity.org/files/2278

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-5, CSCv7|11.5

Plugin: Juniper

Control ID: b3619d8f0cb94b38b6ca50748cc819333d710888d56a277b8adb6028138f2c2a