1.11 Ensure system-wide crypto policy is FUTURE or FIPS

Information

The system-wide crypto-policies followed by the crypto core components allow consistently deprecating and disabling algorithms system-wide.

The individual policy levels (DEFAULT, LEGACY, FUTURE, and FIPS) are included in the crypto-policies(7) package.

Rationale:

If the Legacy system-wide crypto policy is selected, it includes support for TLS 1.0, TLS 1.1, and SSH2 protocols or later. The algorithms DSA, 3DES, and RC4 are allowed, while RSA and Diffie-Hellman parameters are accepted if larger than 1023-bits.

These legacy protocols and algorithms can make the system vulnerable to attacks, including those listed in RFC 7457

FUTURE: Is a conservative security level that is believed to withstand any near-term future attacks. This level does not allow the use of SHA-1 in signature algorithms. The RSA and Diffie-Hellman parameters are accepted if larger than 3071 bits. The level provides at least 128-bit security

FIPS: Conforms to the FIPS 140-2 requirements. This policy is used internally by the fips-mode-setup(8) tool which can switch the system into the FIPS 140-2 compliance mode. The level provides at least 112-bit security

Impact:

Environments that require compatibility with older insecure protocols may require the use of the less secure LEGACY policy level.

Systems configured to use system-wide crypto policy of Future or FIPS will no longer accept connections from openSSH clients that do not support sha2 pub key types

openSSH clients may need to explicitly override and modify PubKeyAcceptedKeyTypes to accept sha2 hashed pub keys

Solution

Run the following command to change the system-wide crypto policy

# update-crypto-policies --set FUTURE

OR
To switch the system to FIPS mode, run the following command:

# fips-mode-setup --enable

Default Value:

DEFAULT

See Also

https://workbench.cisecurity.org/files/3366