Dell EMC Configuration Guide for the S3100 Series 9.14.2.4

SNMPv3 is compliant with the Federal information processing standard (FIPS) cryptography standard. The Advanced Encryption Standard (AES) Cipher Feedback (CFB) 128-bit encryption algorithm is in compliance with RFC 3826. SNMPv3 provides multiple authentication and privacy options for user configuration. A subset of these options are the FIPS-approved algorithms: HMAC-SHA1-96 for authentication and AES128-CFB for privacy. The other options are not FIPS-approved algorithms because of known security weaknesses. The AES128-CFB privacy option is supported and is compliant with RFC 3826.

The SNMPv3 feature also uses a FIPS-validated cryptographic module for all of its cryptographic operations when the system is configured with the fips mode enable command in Global Configuration mode. When the FIPS mode is enabled on the system, SNMPv3 operates in a FIPS-compliant manner, and only the FIPS-approved algorithm options are available for SNMPv3 user configuration. When the FIPS mode is disabled on the system, all options are available for SNMPv3 user configuration.

The following table describes the authentication and privacy options that can be configured when the FIPS mode is enabled or disabled:

To enable security for SNMP packets transferred between the server and the client, you can use the snmp-server user username group groupname 3 auth authentication-type auth-password priv aes128 priv-password command to specify that AES-CFB 128 encryption algorithm needs to be used.

DellEMC(conf)#snmp-server user snmpguy snmpmon 3 auth sha AArt61wq priv aes128 jntRR59a

In this example, for a specified user and a group, the AES128-CFB algorithm, the authentication password to enable the server to receive packets from the host, and the privacy password to encode the message contents are configured.

SHA authentication needs to be used with the AES-CFB128 privacy algorithm only when FIPS is enabled because SHA is then the only available authentication level. If FIPS is disabled, you can use MD5 authentication in addition to SHA authentication with the AES-CFB128 privacy algorithm

You cannot modify the FIPS mode if SNMPv3 users are already configured and present in the system. An error message is displayed if you attempt to change the FIPS mode by using the fips mode enable command in Global Configuration mode. You can enable or disable FIPS mode only if SNMPv3 users are not previously set up. If previously configured users exist on the system, you must delete the existing users before you change the FIPS mode.

Keep the following points in mind when you configure the AES128-CFB algorithm for SNMPv3:

1. SNMPv3 authentication provides only the sha option when the FIPS mode is enabled.

2. SNMPv3 privacy provides only the aes128 privacy option when the FIPS mode is enabled.

3. If you attempt to enable or disable FIPS mode and if any SNMPv3 users are previously configured, an error message is displayed stating you must delete all of the SNMP users before changing the FIPS mode.

4. A message is logged indicating whether FIPS mode is enabled for SNMPv3. This message is generated only when the first SNMPv3 user is configured because you can modify the FIPS mode only when users are not previously configured. This log message is provided to assist your system security auditing procedures.