SNMP RW (Read-Write) access allows stations with Management access to both read and write SNMP MIB objects. Rationale: SNMP is typically used for monitoring specific operational characteristics of the switch. These tasks typically only require read access. Permitting RW (Read-Write) access permits SNMP to modify some SNMP values. Impact: Permitting SNMP RW Access not only allows 'write' access to some SNMP MIB Objects, which allows a malicious attacker to modify some operational characterstics of the switch. By extension this access allows a malicious actor to collect the entire configuration of the device.
Solution
Only use RO groups for SNMPv2. The most common implementation is 'network-operator', because if you use the legacy syntax: switch(config)# snmp-server community <some complex string> ro the switch will translate this to the new syntax, using 'network-operator' group switch(config)# snmp-server community <some complex string> group network-operator Default Value: SNMP is not configured by default. The default SNMP Groups and permissions are: switch# sho snmp group Role: aaa-db-admin Description: Predefined AAA DB admin, has no cli permissions. Allows RESTful A PI ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 permit read-write Role: aaa-db-operator Description: Predefined AAA DB operator, has no cli permissions. Allows RESTfu l API ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 permit read Role: l3-db-admin Description: Predefined L3 DB admin, has no cli permissions. Allows RESTful AP I ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 permit read-write Role: l3-db-operator Description: Predefined L3 DB operator, has no cli permissions. Allows RESTful API ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 permit read Role: network-admin Description: Predefined network admin role has access to all commands on the switch ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 permit read-write Role: network-operator Description: Predefined network operator role has access to all read commands on the switch ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 permit read Role: nxdb-admin Description: Predefined nxdb-admin role has no cli permissions. Allows json-rpc get and set. ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 deny command Role: nxdb-operator Description: Predefined nxdb-operator role has no cli permissions. Allows json-rpc get. ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 deny command Role: vdc-admin Description: Predefined vdc admin role has access to all commands within a VDC instance ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 permit read-write Role: vdc-operator Description: Predefined vdc operator role has access to all read commands within a VDC instance ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 permit read Role: dev-ops Description: Predefined system role for devops access. This role cannot be modified. ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 6 permit command conf t ; username * 5 permit command attach module * 4 permit command slot * 3 permit command bcm module * 2 permit command run bash * 1 permit command python * Role: priv-15 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 permit read-write Role: priv-14 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 1 permit read-write Role: priv-13 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-12 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-11 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-10 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-9 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-8 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-7 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-6 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-5 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-4 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-3 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-2 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-1 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) Role: priv-0 Description: This is a system defined privilege role. Vlan policy: permit (default) Interface policy: permit (default) Vrf policy: permit (default) ------------------------------------------------------------------- Rule Perm Type Scope Entity ------------------------------------------------------------------- 10 permit command traceroute6 * 9 permit command traceroute * 8 permit command telnet6 * 7 permit command telnet * 6 permit command ping6 * 5 permit command ping * 4 permit command ssh6 * 3 permit command ssh * 2 permit command enable * 1 permit read