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The Photon operating system must enable symlink access control protection in the kernel.


Finding ID Version Rule ID IA Controls Severity
V-258841 PHTN-40-000105 SV-258841r933584_rule High
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 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 insecure file system accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of open() or creat().
VMware vSphere 8.0 vCenter Appliance Photon OS 4.0 Security Technical Implementation Guide 2023-10-29


Check Text ( C-62581r933582_chk )
At the command line, run the following command to verify symlink protection is enabled:

# /sbin/sysctl fs.protected_symlinks

Example result:

fs.protected_symlinks = 1

If the "fs.protected_symlinks" kernel parameter is not set to "1", this is a finding.
Fix Text (F-62490r933583_fix)
Navigate to and open:


Add or update the following line:

fs.protected_symlinks = 1

At the command line, run the following command to load the new configuration:

# /sbin/sysctl --load /etc/sysctl.d/zz-stig-hardening.conf

Note: If the file zz-stig-hardening.conf does not exist, it must be created.