Detections
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RHEL-10-701070 - RHEL 10 must enable kernel parameters to enforce discretionary access control (DAC) on hardlinks.

Information

By enabling the "fs.protected_hardlinks" kernel parameter, users can no longer create soft or hard links to files they do not own. Disallowing such hardlinks mitigates vulnerabilities based on insecure file systems accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of open() or creat().

Satisfies: SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000324-GPOS-00125

Solution

Configure RHEL 10 to enable DAC on hardlinks.

Create a drop-in if it does not already exist:

$ sudo vi /etc/sysctl.d/99-fs_protected_hardlinks.conf

Add the following to the file:

fs.protected_hardlinks = 1

Reload settings from all system configuration files with the following command:

$ sudo sysctl --system

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_RHEL_10_V1R1_STIG.zip

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-3(4), 800-53|AC-6(10), CAT|II, CCI|CCI-002165, CCI|CCI-002235, Rule-ID|SV-281309r1184631_rule, STIG-ID|RHEL-10-701070, Vuln-ID|V-281309

Plugin: Unix

Control ID: 9fe61185d92cae945d3661574a091c2c889b33cf1c1f65c59596b1ec41c0d67e