The security implications of not having a read-only WordPress file system
One critical security concern that is often overlooked is the need to set the file system, especially sensitive directories such as /wp-content/plugins
and /wp-content/themes
, to read-only. The subject of /wp-content/uploads
read-only folder is much larger and require a separate article, so here we are going to focus only on plugins and themes.
When the file system of a WordPress website is not set to read-only, it opens the door for hackers to modify the files, inject malicious code, or install backdoors, significantly increasing the risk of a website compromise. Here's why this security vulnerability matters, and how reputable hosting providers address it.
wp-content
Directory is Critical
Why the The wp-content
directory is very important for any WordPress site. It houses essential files that make up your website’s themes and plugins, which in turn define the design and functionality of your site. Here’s a breakdown of key components that live in wp-content
:
wp-content/plugins
: This folder contains all the plugins that extend the functionality of your WordPress site. Plugins range from simple SEO tools to complex e-commerce functionality.wp-content/themes
: This folder stores your active theme and any other themes you've installed. Your theme defines your site's layout and design.
Because these directories contain executable PHP files, they are a prime target for malicious actors looking to exploit vulnerabilities. If a hacker gains access to these files and they are writable, they can alter them to inject malicious code, create new vulnerabilities, or disable key security mechanisms on your site.
Security Risks of Writable Directories
When the file system of a WordPress site is not set to read-only, especially in critical folders like /wp-content/plugins
and /wp-content/themes
, it introduces several security risks:
Code Injection: Hackers can modify PHP files in the
wp-content
directory to inject malicious code such as malware, phishing scripts, or spammy links. This allows them to take over the site, steal sensitive user data, or use the compromised website to distribute malware to visitors.Backdoors: Backdoors are hidden scripts that hackers leave behind to retain access to a compromised site even after the initial vulnerability has been fixed. Writable directories make it easier for hackers to plant backdoors, allowing them to return to the site later to exploit it further.
Theme or Plugin Tampering: If a hacker gains access to a theme or plugin file, they can modify the functionality or break the site entirely. For example, a malicious actor could change a plugin to send sensitive information, such as user passwords or payment details, to a third party.
Breaking Site Functionality: While hackers may have malicious intent, unintended consequences can occur from modifying theme and plugin files. A poorly written or malicious modification could crash the site, introduce errors, or render the website unusable.
SEO Damage and Blacklisting: Hackers often inject links to malicious or spammy websites into compromised WordPress sites, which can severely damage SEO rankings. Worse, if your site is found to be serving malware or spam, it could be blacklisted by Google and other search engines, causing significant loss of traffic and credibility.
How Reputable WordPress Hosts Mitigate These Risks
Many reputable WordPress hosting providers have recognized the dangers associated with writable file systems. To mitigate the risks, they often implement the following security measures:
Locking Down File Editing: Hosting providers can disable the ability to edit files directly from the WordPress admin dashboard. This is done by setting the
DISALLOW_FILE_EDIT
constant totrue
in thewp-config.php
file. This simple measure prevents anyone, including hackers, from modifying theme and plugin files via the WordPress dashboard.Read-Only Permissions for Key Directories: Top-tier WordPress hosting providers often set the
/wp-content/plugins
and/wp-content/themes
directories to read-only. This ensures that even if a hacker gains access to the file system, they cannot modify the critical executable files that power the site.Automatic File Integrity Monitoring: Some hosting providers offer file integrity monitoring services, which alert administrators whenever changes are made to sensitive files. This allows for the quick detection of unauthorized modifications, enabling site owners to act before the damage escalates.
Version Control and Backups: Reputable hosts often maintain automatic backups and version control systems. If malicious code is introduced, administrators can quickly restore the site to a previous, uninfected state, minimizing downtime and loss.
Limited Access Controls: Limiting access to files through permissions (i.e., assigning correct read/write access only to necessary users or processes) and ensuring that users with administrative privileges use strong passwords and two-factor authentication is essential. Hosting providers often enforce these best practices to minimize the risk of compromised credentials leading to file system vulnerabilities.
Conclusion
Leaving the WordPress file system, particularly directories like /wp-content/plugins
and /wp-content/themes
, writable can expose your website to severe security risks, including code injection, backdoors, and site functionality breaks. Reputable hosting providers mitigate these risks by enforcing read-only permissions and disabling file editing capabilities. As a WordPress site owner, it is essential to adopt these best practices to protect your site from becoming a target of malicious actors.
By securing your file system, you not only improve the security of your website but also protect the integrity of your business and the trust of your users.