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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-258841	PHTN-40-000105	SV-258841r933584_rule		High

Description
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().

Description

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().

STIG	Date
VMware vSphere 8.0 vCenter Appliance Photon OS 4.0 Security Technical Implementation Guide	2023-10-29

Details

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: /etc/sysctl.d/zz-stig-hardening.conf 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.