Detections
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1.42 ALMA-09-007170

Information

AlmaLinux OS 9 must enable kernel parameters to enforce discretionary access control (DAC) on symlinks.

GROUP ID: V-269145
RULE ID: SV-269145r1050027

By enabling the fs.protected_symlinks kernel parameter, symbolic links are permitted to be followed only when outside a sticky world-writable directory, or when the user identifier (UID) of the link and follower match, or when the directory owner matches the symlink's owner.

Disallowing such symlinks helps mitigate vulnerabilities based on unsecure file systems accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of open() or creat().

Solution

Configure AlmaLinux OS 9 to enable DAC on symlinks with the following command:

$ echo "fs.protected_symlinks = 1" > /etc/sysctl.d/60-symlinks.conf

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

$ sysctl --system

See Also

https://workbench.cisecurity.org/benchmarks/27039

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-6(10), CCI|CCI-002235, Rule-ID|SV-269145r1050027_rule, STIG-ID|ALMA-09-007170, Vuln-ID|V-269145

Plugin: Unix

Control ID: de70c940d2e34b5cf0aa9104d58f02e58bcb72f3151eb3c42f73e331a1f7ca30