SNMP

Simple Network Management Protocol (SNMP) is used by many individuals and organisations to manage network devices. SNMP communicates over UDP 161. Each network device contains an SNMP agent which connects with an SNMP server. The most popular versions of SNMP today are SNMPv2c and SNMPv3. SNMPv2c uses community strings. These are passwords applied to a device which allow an admin to restrict access by providing read-only or read-write access.

All managed device info is kept in a database called the Management Information Base (MIB). A typical SNMP attack involves an attacker looking for default passwords. This weakness is partially resolves with SNMPv3 as it uses usernames and passwords, but these can still be attacked via brute-force or dictionary.