The Simple Network Management Protocol (SNMP) is a commonly used
network service. Its primary function is to provide network
administrators with information about all kinds of network connected
devices. SNMP can be used to get and change system settings on a
wide variety of devices, from network servers, to routers and
printers. The drawback to this service is the authentication is an
unencrypted "community string". In addition many SNMP servers
provide very simple default community strings. The community string
"all" is a default on a number of SNMP servers.
This community string can allow attackers to gain a large amount
of information about the SNMP server and the network it monitors.
Attackers may even reconfigure or shut down devices remotely.