File permissions are the access rules that decide which users or processes can read, write, or execute a file. On web servers, they are a basic control for limiting what a website, a plugin, or a system account can change. Proper permissions help enforce least privilege, so only trusted components can modify code, upload content, or run scripts.
In cyber security, weak file permissions can turn a minor web compromise into full site takeover. If attacker-controlled code can write into web roots, config files, or executable directories, it can drop web shells, alter pages, or persist after cleanup. Defenders reduce this risk by removing unnecessary write access, separating content from executable files, and disabling file editing in admin panels when possible. Regular permission audits, especially after updates or plugin changes, help spot dangerous misconfigurations before attackers exploit them.