PHP : File permission manipulation

The application changes the file access permissions. The extra permissions (e.g., the right to execute) for an unlimited number of users can facilitate the organization of the attack.

Unix-like systems use the commands chmod, chgrp, chown for rights management. Here, the “file” is understood in a broad sense - file, directory, socket, symbolic link, etc. For each file there are three groups of users: the file owner (user), the group to which the file owner belongs (group) and the rest (other). Each group can have the following access rights: read, write, and execute (abbreviated as r, w, and x, respectively).

Function chmod plays an important role in PHP programming, especially when working with files or editing setting of content management systems (CMS), forums, and guestbooks. Although chmod is used by PHP only in Unix-like operating systems, web hosting servers are usually based on a Unix-like OS. Permissions for chmod in PHP are only written in numeric format with a leading zero, indicating octal notation (e.g., 0777 for rwxrwxrwx).