2.3 Ensure RE firewall filter includes explicit term for SNMP (when SNMP is used)

Information

Routing Engine Firewall Filter should restrict SNMP sources

Rationale:
Firewall filters are built up of one or more terms, which are evaluated in order until either one is matched (at which point the terms then action is taken) or the final term has been evaluated, at which point the default action is to discard the packet.
SNMP provides detailed information about the router and may allow changes to the routers configuration, making SNMP a prime target for an attacker. To protect the router, you should only allow authorized management hosts, ideally on an internal network segment, to connect using SNMP.
Permitted SNMP connections should be logged to the local routing engine and to SYSLOG, allowing a record of connections to be kept and potential attacks to be detected.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

To create a firewall filter term enter the following command from the [edit firewall family <family> filter <filter name>] hierarchy.
[edit firewall family inet filter <filter name>]
user@host#edit term <term name>

[edit firewall family inet filter <filter name> term <term name>]
user@host#set from source-address <authorized address or subnet>
user@host#set from source-address <authorized address or subnet 2>
user@host#set from protocol udp
user@host#set from destination-port snmp
user@host#set then accept
user@host#set then syslog
user@host#set then log

Default Value:
No firewall filters are configured by default.

See Also

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

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-7, CSCv7|11.7, CSCv7|12.4

Plugin: Juniper

Control ID: 45e166f5b315d9e49e67b2b40dac3a4b6c1e8d8a39ee88797a6e69789e637f2f