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

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
high	V-258841	SRG-OS-000324-GPOS-00125	PHTN-40-000105	SV-258841r958726_rule	2024-07-11	2

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().

ℹ️ Check
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
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.