An SNMP community string permits read-only access to all objects. Rationale: The default community string 'public' is well known. Using easy to guess, well known community string poses a threat that an attacker can effortlessly gain unauthorized access to the device. Impact: To reduce the risk of unauthorized access, Organizations should disable default, easy to guess, settings such as the 'public' setting for snmp-server community.
Solution
Disable the default SNMP community string 'public' hostname(config)#no snmp-server community {public}