SNMP
SNMP (Simple Network Management Protocol, RFC 1157, with the SNMPv3 security model defined in RFC 3411) is used to monitor and configure network equipment -- routers, switches, printers, and other managed devices -- by reading and writing values from a device's management information base. SNMPv1 and v2c authenticate requests with a plaintext "community string" (often left at the vendor default, commonly "public" for read access), sent unencrypted and with no protection against an attacker guessing or sniffing it; SNMPv3 added real authentication and encryption, but many devices still ship or get deployed with the older, weaker versions enabled for compatibility. A device that answers SNMP queries from the open internet, especially with a default community string, can leak configuration and network-topology details, or in some implementations have its configuration changed by anyone who can reach it.
By AdminKit team, Netbase JSC · Updated