In combination with other strategies, PHP safe mode is enabled on the Ilisys Linux cluster to minimise your exposure to malicious attacks against web applications.

Every day, numerous exploits are reported that exploit security vulnerabilities in common applications such as forums, content management systems and image galleries. While popular open source projects are regularly subject to attack, privately developed software is often just as vulnerable.

Safe mode prevents directory traversal
Your scripts can only access files within your own website directory. This prevents an attacker from using code within one comprimised website to view configuration files or sensitive information that belong to another website.

Safe mode limits script execution time
Safe mode sets a maximum script execution time to ensure that scripts cannot cause denial of service through monopolisation of processor resources within the Linux cluster.

Safe mode limits memory utilisation
Safe mode sets a maximum memory usage to ensure that scripts cannot cause denial of service through RAM monopolisation within the Linux cluster.

Safe mode limits access to system functions
Functions such as exec(), unlink(), and copy() are given strict conditions of usage to prevent abuse. A comprehensive guide to these limited functions is available here.

PHP safe mode is a necessary preventative measure to assist the security and availability of your website. More general safe mode information is available here.

Ilisys staff are experienced at helping customers work with PHP safe mode. If you would like help using your script or web application, please contact Technical Support (support@ilisys.com.au or 1800 995 645).