Configure SSH Client to Use FIPS 140-2 Validated MACs: openssh.config
An XCCDF Rule
Description
Crypto Policies provide a centralized control over crypto algorithms usage of many packages.
OpenSSH is supported by system crypto policy, but the OpenSSH configuration may be
set up incorrectly.
To check that Crypto Policies settings are configured correctly, ensure that
/etc/crypto-policies/back-ends/openssh.config contains the following
line and is not commented out:
MACs
warning alert: Warning
The system needs to be rebooted for these changes to take effect.
warning alert: Regulatory Warning
System Crypto Modules must be provided by a vendor that undergoes
FIPS-140 certifications.
FIPS-140 is applicable to all Federal agencies that use
cryptographic-based security systems to protect sensitive information
in computer and telecommunication systems (including voice systems) as
defined in Section 5131 of the Information Technology Management Reform
Act of 1996, Public Law 104-106. This standard shall be used in
designing and implementing cryptographic modules that Federal
departments and agencies operate or are operated for them under
contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf
To meet this, the system has to have cryptographic software provided by
a vendor that has undergone this certification. This means providing
documentation, test results, design information, and independent third
party review by an accredited lab. While open source software is
capable of meeting this, it does not meet FIPS-140 unless the vendor
submits to this process.
Rationale
Overriding the system crypto policy makes the behavior of the OpenSSH client violate expectations, and makes system configuration more fragmented.
- ID
- xccdf_org.ssgproject.content_rule_harden_sshd_macs_openssh_conf_crypto_policy
- Severity
- Medium
- References
- Updated