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Ubuntu OS must configure the SSH daemon to use Message Authentication Codes (MACs) employing FIPS 140-2/140-3 -approved cryptographic hashes to prevent the unauthorized disclosure of information and/or detect changes to information during transmission.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-275625RIIM-OS-255055SV-275625r1147925_ruleCCI-001453high
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. Nonlocal maintenance and diagnostic activities are those activities conducted by individuals communicating through a network, either an external network (e.g., the internet) or an internal network. Local maintenance and diagnostic activities are those activities carried out by individuals physically present at the information system or information system component and not communicating across a network connection. Encrypting information for transmission protects information from unauthorized disclosure and modification. Cryptographic mechanisms implemented to protect information integrity include, for example, cryptographic hash functions, which have common application in digital signatures, checksums, and message authentication codes. Satisfies: SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000424-GPOS-00188
STIGDate
Riverbed NetIM OS Security Technical Implementation Guide2025-10-02

Related Frameworks

1 mapping across 4 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (1) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

NET-14.2Protection of Confidentiality / Integrity Using Encryption
1.00
NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (31) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

AC-17(1)Monitoring and Control
1.00
AC-17(2)Protection of Confidentiality and Integrity Using Encryption
1.00
AC-3Access Enforcement
1.00
CM-6Configuration Settings
1.00
CM-7Least Functionality
1.00
IA-2(8)Access to Accounts — Replay Resistant
1.00
IA-2(9)Network Access to Non-privileged Accounts — Replay Resistant
1.00
IA-3Device Identification and Authentication
1.00
IA-3(1)Cryptographic Bidirectional Authentication
1.00
IA-5(1)Password-based Authentication
1.00

+21 more (top 10 by confidence shown)

NIST 800-1710 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (1) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

3.1.13
1.00
CCI1 mapping
CCI-001453
1.00

Details

Check Text (C-275625r1147925_chk)

Verify the SSH server is configured to only use MACs that employ FIPS 140-2/140-3-approved ciphers by using the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH 'macs' /etc/ssh/sshd_config:MACs hmac-sha2-512,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha2-256-etm@openssh.com If "MACs" does not contain only the hashes "hmac-sha2-512,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha2-256-etm@openssh.com" in exact order, is commented out, is missing, or conflicting results are returned, this is a finding.

Fix Text (F-79632r1147924_fix)

Configure the SSH server to only use MACs that employ FIPS 140-2/140-3-approved hashes. Add or modify the following line in the "/etc/ssh/sshd_config" file: MACs hmac-sha2-512,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha2-256-etm@openssh.com Restart the SSH server for the changes to take effect: $ sudo systemctl reload sshd.service