Does Junos OS support the user-based security model (USM)?
Yes, Junos OS supports USM as part of its support for SNMPv3. SNMPv3 contains more security measures than previous versions of SNMP, including providing a defined USM. SNMPv3 USM provides message security through data integrity, data origin authentication, message replay protection, and protection against disclosure of the message payload.
For more information, click Understanding SNMP implementation in Junos OS.