What is a backdoor?

A backdoor is a mechanism that allows unauthenticated access to a system. Essentially, it bypasses the primary defenses of a website, providing a hidden door through which someone can access a given system anytime they please. While backdoor software is generally associated with hackers and other malicious actors, there are several use cases in which a backdoor serves a legitimate purpose.

How do backdoors work?

Backdoors can be implemented in various ways. Some backdoors are put in place by design; that is to say, the software developers put them there by design. Others are installed through a
3rd party software or hardware devices, while others are a security flaw.

By design

Some manufacturers design backdoors that are baked into the software. These are installed by design and can help manufacturers carry out certain tasks, such as resetting passwords for locked-out users. There have also been allegations of state actors requiring manufacturers to design backdoors allowing for remote control of devices. Such backdoors are frequent carriers of controversy since it infringes on users’ right to privacy.

By installation

A malicious actor may install a backdoor on a system to ensure easy recurrent access to that system. Such backdoors are installed following an initial security breach, which may be an active breach or a passive breach. An active breach involves the malicious actor identifying a security hole through which an initial breach takes place. Backdoor installation can also be automated through malware such as trojans. Either way, once the initial breach has been accomplished, a backdoor software program is subsequently installed, giving the person an easy way for recurrent access.

By flaw

System imperfections, otherwise known as vulnerabilities, can open unintentional backdoors. While this does not generally manifest on web applications such as WordPress, other kinds of software such as Operating Systems may be vulnerable to such attacks.

Why are backdoors dangerous?

Backdoors are dangerous for several reasons. In most cases, backdoor access comes with administrative privileges, providing full access to all of WordPress and its resources. This can lead to all kinds of attacks, including data theft and website takeover. Aside from the direct financial and reputational repercussions, this can also lead to penalties.

Backdoors can also be used to redirect traffic to another website, send spam emails to your users, take over advertising, and store pirated data, among other things. All of these can lead to visitor loss and demotion of your website.

Backdoors installed by design have also been a major source of controversy, with companies denied access to entire markets due to allegations that their software had such backdoors. One such high-profile case is that of Huawei, which has been banned from doing business in the US amidst allegations that its products were used to spy on other countries.

How backdoors can be introduced to WordPress websites

Although WordPress is generally very secure, it is not entirely immune to backdoor attacks. In many instances, additional code is added to WordPress in the form of themes and plugins, which can open the door to backdoor installation and attacks.

Plugins and themes can present a security flaw, either intentionally or unintentionally. Fortunately, both are relatively easy to avoid.

Intentional security flaws are introduced by plugins and themes that are malicious in the first place. Oftentimes, such software makes exaggerated claims, luring users into thinking they are getting a great deal. To avoid installing such software, always verify the vendor and read customer reviews to better understand the company and how it interacts with its customers.

Unintentional security flaws are something that we have less control over but can be avoided nevertheless. All software can have vulnerabilities, from Windows Operating Systems to WordPress and everything in between. The same is true for WordPress plugins and themes. These vulnerabilities can open the door for malicious actors to install backdoors on the system.

Reputable vendors, however, employ rigorous testing ensuring instances of such vulnerabilities are kept to a minimum. Frequent updates, which deal with such vulnerabilities, among other things, are something else to look out for. This ensures that the developers are responsive to whatever issues may arise, and you won’t have to wait too long for a fix should a vulnerability be discovered.

How to protect your WordPress website from backdoors

Fortunately, there are several steps you can take to ensure that your WordPress website is as protected as possible. Many of these are considered security best practices and will protect your WordPress website from different types of attacks.

Harden WordPress

WordPress is a relatively secure application, but this does not mean we cannot do more to make it even more secure. Hardening WordPress and ensuring WordPress file permissions are set up right can help you mitigate many of the risks, as is applying the principle of least privilege.

Only install plugins from reputable vendors

Reputable vendors have a lot more at stake and are more likely to test their plugins before releasing them for public consumption thoroughly. This can help you make sure that most security flaws are fixed before the plugin is released. It is also wise to check how often the plugin vendor release updates. If the latest version has been released for a few good months, you might want to stay away.

Scan files for changes

Backdoors are installed within the filesystem of a website, so checking WordPress files for any changes can help you catch a backdoor early on. File scanners designed for WordPress, such as Website File Changes Monitor Plugin for WordPress, use a hashing algorithm to detect even the most minute of changes, helping you detect the sneakiest of intrusions with minimal effort.

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