SAP System Security Under UNIX/LINUX 
This section discusses security under the UNIX or LINUX operating system, including recommendations and preventive measures.
Setting Access Privileges for SAP System Directories Under UNIX/
Additional Information on UNIX/LINUX Security
CautionThe most important recommendation for securing your system at the operating system level is to keep your operating system up to date. Make sure you stay informed and install any security-related patches that are released by your operating system vendor.
End of the caution.