Common WordPress vulnerabilities

Posted on May 2, 2023 at 8:28 am

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WordPress is a widely popular content management system (CMS) used by many individuals, businesses, and organizations. While it offers flexibility and easy customization, it also has its fair share of security vulnerabilities. With its popularity, it becomes a prime target for hackers and cybercriminals to exploit these weaknesses and gain unauthorized access to a website.

In this article, we will discuss some of the most common WordPress vulnerabilities and attacks, providing readers with valuable insight on how to secure their websites. By understanding these risks, website owners and developers can take the necessary precautions to protect their data and prevent any unwanted breaches.

It is crucial to take these security concerns seriously as an attack can not only damage a website's reputation but also result in significant financial losses. The impact of a breach can differ depending on the intensity of the damage and the type of attack. For instance, a Denial of Service (DoS) attack can render a website inaccessible to users, resulting in a loss of revenue and potential customers.

With cyber threats becoming increasingly sophisticated, it is no longer enough to have basic security measures in place. Website owners need to stay vigilant and ensure they have the right security measures in place to protect their sites from potential attacks. So, let us dive in and see what we need to know about common WordPress vulnerabilities.

SQL Injection Attacks

SQL injection attacks are a type of cyber attack where an attacker exploits vulnerabilities in a website's code to inject malicious SQL code. The injected code allows the attacker to gain unauthorized access to sensitive data stored in the website's database.

SQL injection attacks are one of the most common forms of web application attacks, accounting for nearly 72% of all web attacks according to a report by Imperva.

The consequences of a successful SQL injection attack can be severe, including theft of sensitive data such as user credentials, credit card information, and personal identifiable information (PII).

For example, in 2017, Equifax, one of the largest credit bureaus in the US, suffered a massive data breach due to a SQL injection vulnerability in their website's code. This breach resulted in the theft of sensitive financial information of over 147 million customers.

To prevent SQL injection attacks, website owners should ensure that their code is secure and implement preventative measures such as regularly updating software, validating input data, and using prepared statements. Regular security audits are also recommended to detect and address vulnerabilities in a timely manner.


Cross-Site Scripting (XSS) Attacks

One of the most common types of web attacks is Cross-Site Scripting (XSS). In this type of attack, an attacker injects malicious code into a web page visited by other users. This code then executes on the user's browser, giving the attacker access to sensitive information such as login credentials, session cookies, and other personal data.

According to a report by Akamai Technologies, XSS attacks accounted for approximately a third of all web attacks in 2019. Moreover, a survey by Trustwave found that 28% of all data breaches in 2019 involved some form of XSS attack.

One common example of an XSS attack involves injecting a script that steals session cookies. The attacker can then use these cookies to impersonate the victim and gain access to their account. Another example is injecting a script that modifies the content of a webpage, such as changing text, adding links, or even redirecting the victim to another page.

One way to protect against XSS attacks is to sanitize user input and escape special characters before displaying them on a webpage. This can be accomplished through various web application security measures such as Content Security Policy (CSP), Input Validation, and Output Encoding. Additionally, developers should avoid the use of eval, innerHTML, and other functions that allow arbitrary code execution.

For further information on how to prevent XSS attacks, refer to the OWASP XSS Prevention Cheat Sheet.

Brute Force Attacks

A brute force attack is an automated method used by cybercriminals to gain unauthorized access to a system or website. It involves trying various username and password combinations until the correct one is found.

These attacks can be devastating for businesses as they can compromise valuable data. A study by Digital Guardian found that 81% of all hacking-related breaches involved stolen or weak passwords.

To carry out a brute force attack, attackers use software that can generate a large number of possible password combinations in a short amount of time. They often use lists of common passwords or dictionaries of words to speed up the process.

Once the correct password is discovered, the attacker gains access to the system or website. They can then steal sensitive information, install malware or ransomware, or carry out other malicious activities.

Fortunately, there are steps businesses and individuals can take to protect themselves against brute force attacks. Here are a few tips:

  • Use strong passwords: Avoid using common or easily guessable passwords. Use a combination of letters, numbers, and special characters to create a unique password for each account you have.

  • Use Two-Factor Authentication (2FA): Two-factor authentication adds an extra layer of security to your accounts. It requires you to enter a code sent to your phone or a physical device in addition to your password.

  • Limit login attempts: Many websites and systems allow you to limit the number of login attempts before locking the account. This prevents cybercriminals from using automated software to generate multiple password attempts.

  • Keep software up-to-date: Brute force attacks can exploit vulnerabilities in outdated software. Keep all software up-to-date, including operating systems, apps, and plugins.

By taking these simple steps, businesses and individuals can protect themselves against brute force attacks and keep their information safe.


Outdated plugins/themes

Outdated plugins/themes are one of the most common vulnerabilities on websites that can be exploited by attackers. According to a report, 55.9% of WordPress hacks were caused by vulnerabilities in outdated plugins and themes.

Hackers can exploit outdated plugins and themes by finding and exploiting known vulnerabilities, which can allow them to gain unauthorized access to the website. This can lead to the installation of malware, defacement of the website, or theft of sensitive data.

It is important to keep all plugins and themes on your website up to date. Developers release updates to fix security vulnerabilities, add new features, and improve performance. Failure to update leaves your website vulnerable to attacks that could have been easily prevented.

WordPress, one of the most popular content management systems, provides an easy way to update plugins and themes automatically. However, you can also manually update them by logging into the WordPress dashboard, navigating to the plugins or themes page, and checking for updates. In some cases, it may be necessary to manually download and install the latest version of a plugin/theme, so always double-check the developer's instructions.

In summary, outdated plugins and themes are a significant risk to website security. Keep plugins and themes updated to reduce the risk of attacks and protect your website from the potential consequences of a data breach.

Useful resources:

Weak Passwords

One of the most common ways for attackers to exploit a website's security is through weak passwords. In fact, according to a recent study, over 80% of data breaches are caused by weak or stolen passwords.

A weak password is any password that can be easily guessed or cracked by attackers. This includes passwords that are too short or simple, passwords that contain common words or phrases, and passwords that are reused across multiple accounts.

To create strong passwords, it is recommended to use a combination of upper and lower case letters, numbers, and symbols. Passwords should also be at least 12 characters long and not contain easily guessable information such as birth dates or pet names.

Another common mistake is reusing the same password across multiple accounts. This means if one password is compromised, all other accounts will also be at risk. To avoid this, it is recommended to use unique passwords for each account or consider a password manager to generate and securely store passwords.

In addition to creating strong passwords, it is important to regularly change passwords and enable two-factor authentication. Two-factor authentication adds an extra layer of security by requiring a second form of identification, such as a text message code or fingerprint scan, in addition to a password.

By taking these steps to strengthen passwords, website administrators can greatly reduce the risk of attacks and keep their website and users safe.

Some resources to learn more about password security and generating strong passwords:

  • National Institute of Standards and Technology Guide to Enterprise Password Management
  • How to Create a Strong Password (And Remember It)
  • 10 Best Password Managers for 2021

User Enumeration

User enumeration is a type of cybersecurity attack in which an attacker tries to discover usernames or other identifying information by exploiting weaknesses in authentication systems. By gathering this information, attackers can then launch more targeted and effective attacks, such as brute force attacks or password cracking attempts.

One common way that attackers perform user enumeration is by attempting to log into a system with a known username and a series of common passwords. By monitoring the response times of login attempts, attackers can often determine whether or not a given username exists in the system, allowing them to slowly build up a list of valid usernames.

Another technique involves using a script or program to repeatedly send requests to a login page with a series of different usernames. If the system produces an error message indicating that a particular username does not exist, the attacker knows that the username is not valid. If the system returns a different error message, indicating that the username exists but the password is incorrect, the attacker has successfully identified a valid username.

According to a report by Verizon, user enumeration attacks are common and occur in approximately 16 percent of data breaches. These attacks are often effective because they allow attackers to gain a foothold in a system without raising any alarms. Once attackers have gathered a list of valid usernames, they can launch more sophisticated attacks to gain access to sensitive information.

To prevent user enumeration attacks, it is important to regularly monitor login attempts and look for patterns of suspicious behavior. Employing multi-factor authentication and making sure that all users have strong, unique passwords can also help to prevent these types of attacks.

In addition to these technical safeguards, user education is also important. All users should be trained to recognize and report suspicious login attempts, and to avoid using the same password across multiple systems. By working together to prevent user enumeration attacks, we can help keep our systems and data secure.

Useful links:

File Inclusion Vulnerabilities

File inclusion vulnerabilities occur when a web application includes a file that can be manipulated by an attacker to execute arbitrary code. This vulnerability can be exploited for several purposes, such as disclosing sensitive information, remote code execution, or even taking control of the application's entire server.

One of the most common types of file inclusion vulnerabilities is Local File Inclusion (LFI). LFI allows attackers to read files on the server by loading them through the web application. This can be particularly dangerous when the web application is running with high-level system privileges.

Remote File Inclusion (RFI) is another type of file inclusion vulnerability where an attacker can execute remote code on the server by including a malicious file in the web application. RFI attacks usually result in a complete compromise of the affected system.

File inclusion vulnerabilities are particularly common in PHP-based web applications. In fact, according to a study conducted by Acunetix, PHP is the most exploited language for these types of vulnerabilities, with 98% of PHP sites showing signs of LFI vulnerabilities.

Protecting against file inclusion vulnerabilities can be done through a combination of measures, such as input validation, file type whitelist, and server-side file access restrictions.


A typical example of an LFI attack would be through a web application that includes a file based on user input, something similar to this:

<code>$file = $_GET['file'];
include($file . ".php");</code>

By manipulating the file parameter in the URL, an attacker could include arbitrary files and execute malicious code on the server. For instance, by setting file to ../../../../etc/passwd, an attacker could read the /etc/passwd file containing all the user accounts on the server.


To prevent file inclusion vulnerabilities, input validation should be used to sanitize user-supplied input and ensure it is a valid path or file name. Any user input should be strictly validated before accepting it, and both server-side and client-side input validation should be used to ensure that the input is clean.

Additionally, to mitigate any damage that may occur in case of vulnerabilities, file access restrictions should also be applied to provide an additional layer of security. File access restrictions can be designed to restrict a web application from accessing system files, keeping the server safe.


File inclusion vulnerabilities are a serious threat to web applications, and they can lead to catastrophic consequences. It is essential to understand how they work and how to prevent them. By following the best practices outlined, developers can significantly reduce the risk of exploitation and keep their applications secure.

XML-RPC Vulnerabilities

XML-RPC, or XML Remote Procedure Call, is a protocol used by various web services to communicate with each other. It has been widely used by blogging platforms for providing remote access to functionalities such as posting articles or managing comments. However, XML-RPC can also create serious vulnerabilities in your website's security.

One of the most glaring issues with XML-RPC is that it provides an easy target for hackers to launch attacks on your website. Since it provides full access to your website's functionality, including the ability to publish or delete posts, a single breach can cause significant damage. In fact, in 2015, the Jetpack plugin for WordPress suffered a major data breach because of a vulnerability in their XML-RPC.

Another issue with XML-RPC is that it can be used in DDoS, or Distributed Denial of Service, attacks. Hackers can use XML-RPC to send massive amounts of traffic to your website, causing it to crash and become unavailable to your visitors. This is because XML-RPC services often allow large payloads, making it easy to overload your server with traffic that may be difficult for it to handle.

To prevent XML-RPC vulnerabilities, you should disable XML-RPC if it is not needed. Several plugins are available that can easily disable XML-RPC functionality for your website, such as Disable XML-RPC for WordPress. If you require XML-RPC for certain functionalities, make sure to restrict access to only trusted users and IP addresses. Additionally, make sure your website's software is up-to-date and fix any vulnerabilities that are identified.

Overall, while XML-RPC can be a useful tool for remote access to website functionalities, it also represents a significant risk to your website's security. Taking the steps to manage this vulnerability can help to secure your website and prevent potential damage from a malicious attack.

Malware and Backdoors

Malware is short for malicious software and is designed to damage, disrupt, or steal data from computers, networks, or devices. It is often spread through spam emails, phishing scams, or infected websites. Malware can take many forms, including viruses, Trojans, ransomware, and spyware.

Backdoors are a type of malware that allows attackers to bypass normal authentication procedures to gain access to a computer system or network. Backdoors can be installed by attackers who exploit vulnerabilities in software, or they may be deliberately included by software developers for maintenance purposes.

According to a report by Malwarebytes, there was a 13% increase in the number of malware attacks in 2020, with ransomware attacks up by 41%. These attacks can have devastating consequences for individuals and businesses alike. In fact, a study by the Ponemon Institute found that the average cost of a data breach is $3.86 million.

To protect against malware and backdoors, it is important to use antivirus software and keep it up-to-date. Regularly scanning your computer or network for malware can help detect and remove any infected files. It is also important to be cautious when clicking on links or downloading attachments in emails, especially if they are from unknown sources.

Additionally, keeping all software, including operating systems, plugins, and themes, up-to-date can help prevent vulnerabilities that attackers can exploit to install malware or backdoors. Creating strong passwords and using two-factor authentication can also help prevent unauthorized access to your accounts and devices.

It is important to note that if you do fall victim to a malware or backdoor attack, it is crucial to immediately disconnect from the internet and seek professional help to remove the infection and secure your system.


Denial of Service (DoS) attacks

A Denial of Service (DoS) attack is a type of cyber attack that targets an organization's website or network, flooding it with traffic, requests, or data to the point where it becomes inaccessible or unusable. These attacks aim to disrupt the normal functioning of a system, rendering it unavailable to its intended users.

DoS attacks have become increasingly prevalent and damaging in recent years. According to a report by Netscout, the number of DoS attacks rose by 16% in the first half of 2020, with an average of 4.83 million attacks per week.

There are various types of DoS attacks, including:

  • Ping flood attack: The attacker sends a large number of ping requests to overwhelm the server or network.
  • UDP flood attack: The attacker sends a large number of User Datagram Protocol (UDP) packets to flood the network.
  • SYN flood attack: The attacker sends a large number of SYN requests to exhaust the server's resources and prevent legitimate users from accessing it.
  • HTTP flood attack: The attacker sends a large number of HTTP requests to overload the server and make it inaccessible.

DoS attacks can have severe consequences for businesses and organizations. They can cause a loss of revenue, damage to reputation, and even legal liability. It's essential for organizations to take proactive measures to protect against these attacks.

Some ways to protect against DoS attacks include:

  • Use traffic filtering: Employing systems that filter out traffic from malicious sources before it reaches the network can be an effective DoS protection measure.
  • Ensure server redundancy: Having multiple servers can help distribute traffic and prevent a single point of failure.
  • Implement DoS protection software: There is software available that can quickly detect and mitigate DoS attacks.
  • Monitor network traffic: Regularly monitoring traffic can help identify unusual patterns and act quickly in the event of a DoS attack.

In conclusion, DoS attacks are a serious threat to organizations' security and reputation. By implementing preventive measures and being vigilant, organizations can minimize the risks of these attacks.

In conclusion, it is important to take measures to protect your WordPress site from the various vulnerabilities that exist. SQL injection attacks, cross-site scripting (XSS) attacks, brute force attacks, and outdated plugins or themes are just a few examples of the types of attacks that your site may be vulnerable to.

To protect your site, it is important to keep your plugins and themes updated to the latest version to ensure they are not exploiting any known vulnerabilities. It is also important to use strong passwords that are difficult to guess, and limit user access where possible.

Another important step in protecting your WordPress website is to implement security measures such as firewalls and malware scanners. This will help to detect and prevent any malicious activity that may be occurring on your site.

In addition, regular backups of your website are essential to ensure that any data or files lost can be retrieved in the event of an attack. Finally, it is recommended to stay up-to-date with the latest cybersecurity information and trends to stay informed and take proactive steps to protect your site.

In summary, the threats to WordPress sites can be vast and varied, but there are tangible steps that can be taken to mitigate them. By staying vigilant and taking preemptive action, you can protect your website and the sensitive information it contains from cyber attacks. Don't wait until it's too late, start implementing best practices today to keep your WordPress site secure.

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