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RHEL 9 must force a frequent session key renegotiation for SSH connections to the server.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-257994RHEL-09-255090SV-257994r1045051_ruleCCI-000068medium
Description
Without protection of the transmitted information, confidentiality and integrity may be compromised because unprotected communications can be intercepted and either read or altered. This requirement applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, and facsimile machines). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification. Protecting the confidentiality and integrity of organizational information can be accomplished by physical means (e.g., employing physical distribution systems) or by logical means (e.g., employing cryptographic techniques). If physical means of protection are employed, then logical means (cryptography) do not have to be employed, and vice versa. Session key regeneration limits the chances of a session key becoming compromised. Satisfies: SRG-OS-000423-GPOS-00187, SRG-OS-000033-GPOS-00014, SRG-OS-000424-GPOS-00188
STIGDate
Red Hat Enterprise Linux 9 Security Technical Implementation Guide2025-05-14

Related Frameworks

3 mappings across 5 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (6) 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.

CRY-01Use of Cryptographic Controls
1.00
CRY-03Transmission Confidentiality
1.00
CRY-04Transmission Integrity
1.00
DCH-01Data Protection
1.00
NET-14.2Protection of Confidentiality / Integrity Using Encryption
1.00
CRY-01.1Alternate Physical Protection
0.50
NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (38) 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-10Concurrent Session Control
1.00
AC-17(1)Monitoring and Control
1.00
AC-17(2)Protection of Confidentiality and Integrity Using Encryption
1.00
AC-18(1)Authentication and Encryption
1.00
AC-3Access Enforcement
1.00
CM-6Configuration Settings
1.00
CM-6(1)Automated Management, Application, and Verification
1.00
CM-7Least Functionality
1.00
CM-7(1)Periodic Review
1.00
IA-11Re-authentication
1.00

+28 more (top 10 by confidence shown)

NIST 800-1710 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (2) 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
3.13.8
1.00
CCI3 mappings
CCI-000068
1.00
CCI-002418
1.00
CCI-002421
1.00
NIST CSF 2.00 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (3) 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.

PR.DS-02
1.00
PR.DS-01
0.50
PR.DS-10
0.50

Who does this work

8 NICE work roles and 7 EC-Council certifications.

This is an inference across published mappings, not a single claim by anyone. This check maps to a control, which maps to a Cybersecurity Framework outcome, which NIST assigns to the work roles below. EC-Council separately maps its certifications to those same roles.

A certification prepares someone for a role. It is not evidence that a holder is qualified, and neither NIST nor EC-Council has stated that any certification here addresses this check.

Work-role assignments published by NIST (NICE Framework Components 2.2.0 and the CSF 2.0 OLIR crosswalk). Certification mappings published by EC-Council.

Details

Check Text (C-257994r1045051_chk)

Verify the SSH server is configured to force frequent session key renegotiation 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*rekeylimit' RekeyLimit 1G 1h If "RekeyLimit" does not have a maximum data amount and maximum time defined, is missing, or is commented out, this is a finding.

Fix Text (F-61659r1045050_fix)

Configure RHEL 9 to force a frequent session key renegotiation for SSH connections to the server by adding or modifying the following line in the "/etc/ssh/sshd_config" or in a file in "/etc/ssh/sshd_config.d": RekeyLimit 1G 1h Restart the SSH daemon for the settings to take effect. $ sudo systemctl restart sshd.service