Vulnerability Discussion

Centralized cryptographic policies simplify applying secure ciphers across an operating system and the applications that run on that operating system. Use of weak or untested encryption algorithms undermines the purposes of using encryption to protect data.

Satisfies: SRG-OS-000396-GPOS-00176, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174

Check

Verify that RHEL 9 cryptographic policies are not overridden.

Verify that the configured policy matches the generated policy with the following command:

$ sudo update-crypto-policies --check && echo PASS

The configured policy matches the generated policy
PASS

If the last line is not "PASS", this is a finding.

List all of the crypto backends configured on the system with the following command:

$ ls -l /etc/crypto-policies/back-ends/

lrwxrwxrwx. 1 root root 40 Nov 13 16:29 bind.config -> /usr/share/crypto-policies/FIPS/bind.txt
lrwxrwxrwx. 1 root root 42 Nov 13 16:29 gnutls.config -> /usr/share/crypto-policies/FIPS/gnutls.txt
lrwxrwxrwx. 1 root root 40 Nov 13 16:29 java.config -> /usr/share/crypto-policies/FIPS/java.txt
lrwxrwxrwx. 1 root root 46 Nov 13 16:29 javasystem.config -> /usr/share/crypto-policies/FIPS/javasystem.txt
lrwxrwxrwx. 1 root root 40 Nov 13 16:29 krb5.config -> /usr/share/crypto-policies/FIPS/krb5.txt
lrwxrwxrwx. 1 root root 45 Nov 13 16:29 libreswan.config -> /usr/share/crypto-policies/FIPS/libreswan.txt
lrwxrwxrwx. 1 root root 42 Nov 13 16:29 libssh.config -> /usr/share/crypto-policies/FIPS/libssh.txt
-rw-r--r--. 1 root root 398 Nov 13 16:29 nss.config
lrwxrwxrwx. 1 root root 43 Nov 13 16:29 openssh.config -> /usr/share/crypto-policies/FIPS/openssh.txt
lrwxrwxrwx. 1 root root 49 Nov 13 16:29 opensshserver.config -> /usr/share/crypto-policies/FIPS/opensshserver.txt
lrwxrwxrwx. 1 root root 46 Nov 13 16:29 opensslcnf.config -> /usr/share/crypto-policies/FIPS/opensslcnf.txt
lrwxrwxrwx. 1 root root 43 Nov 13 16:29 openssl.config -> /usr/share/crypto-policies/FIPS/openssl.txt
lrwxrwxrwx. 1 root root 48 Nov 13 16:29 openssl_fips.config -> /usr/share/crypto-policies/FIPS/openssl_fips.txt

If the paths do not point to the respective files under /usr/share/crypto-policies/FIPS path, this is a finding.
Note: nss.config should not be hyperlinked.

Fix

Configure RHEL 9 to correctly implement the systemwide cryptographic policies by reinstalling the crypto-policies package contents.

Reinstall crypto-policies with the following command:

$ sudo dnf -y reinstall crypto-policies

Set the crypto-policy to FIPS with the following command:

$ sudo update-crypto-policies --set FIPS

Setting system policy to FIPS

Note: Systemwide crypto policies are applied on application startup. It is recommended to restart the system for the change of policies to fully take place.