AlmaLinux OS 9 must implement DOD-approved systemwide cryptographic policies to protect the confidentiality of SSH server connections.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-269118	SRG-OS-000250-GPOS-00093	ALMA-09-003430	SV-269118r1050609_rule	2025-02-20	1

Description
Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash.

Description

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access (e.g., RDP) is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash.

ℹ️ Check
Verify that systemwide crypto policies are in effect with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 \| awk '/filename/ {print $4}' \| tr -d '\r' \| tr '\n' ' ' \| xargs sudo grep -iH '^\sinclude' /etc/ssh/sshd_config:Include /etc/ssh/sshd_config.d/.conf /etc/ssh/sshd_config.d/50-redhat.conf:Include /etc/crypto-policies/back-ends/opensshserver.config If "Include /etc/ssh/sshd_config.d/*.conf" or "Include /etc/crypto-policies/back-ends/opensshserver.config" are not included in the system sshd config or the file /etc/ssh/sshd_config.d/50-redhat.conf is missing, this is a finding.

ℹ️ Check

Verify that systemwide crypto policies are in effect with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*include' /etc/ssh/sshd_config:Include /etc/ssh/sshd_config.d/*.conf /etc/ssh/sshd_config.d/50-redhat.conf:Include /etc/crypto-policies/back-ends/opensshserver.config If "Include /etc/ssh/sshd_config.d/*.conf" or "Include /etc/crypto-policies/back-ends/opensshserver.config" are not included in the system sshd config or the file /etc/ssh/sshd_config.d/50-redhat.conf is missing, this is a finding.

✔️ Fix
Configure the AlmaLinux OS 9 SSH daemon to use systemwide crypto policies by running the following commands: $ sudo dnf reinstall openssh-server