What is Remote File Inclusion in WordPress?

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Remote file inclusion feature image

Did you know that even a small vulnerability in your website could let a hacker in?

Imagine logging in for routine maintenance only to find your site defaced, your content replaced with malicious material, and visitors reporting malware.These incidents are often the result of various WordPress site attacks, where hackers exploit vulnerabilities to gain unauthorized access.

If you can relate to any of these situations, it’s time to scan your website now.

This nightmare can become a reality through remote file inclusion (RFI) attacks, where hackers inject harmful files into your site, causing data breaches and server takeovers.

But don’t panic just yet! Protecting your WordPress site from these nasty intrusions isn’t hard. With some knowledge and preventive steps, you can protect your site and keep it secure.

TL;DR: Remote file inclusion (RFI) is a vulnerability that allows hackers to inject malware into your WordPress site. Malware causes data theft, site defacement, and complete site takeover. You can protect your site with regular updates and use MalCare to fortify your site’s defense. 

What is remote file inclusion?

Remote file inclusion (RFI) is a serious website security vulnerability. It allows an attacker to trick your website into thinking that a malicious file from a remote location is a part of your website. The goal? Unauthorized code execution, data theft, and sometimes even full control over the compromised site.

You may be wondering why a website would allow remote code to be executed at all, malicious intent or other. As it turns out, there are legitimate reasons for remote code execution: CDNs, cloud services, and even WordPress updates. The key difference lies in the intention, and the use of trusted and verified sources that you, the website owner, choose to allow. 

In an RFI attack, the attacker exploits a vulnerability to force the website to include and execute arbitrary, malicious remote code. The website server fetches and runs these files, which leads to successful breaches and attacks.

The WP TimThumb exploit is a well-known RFI issue. TimThumb is a script that resizes images in WordPress themes. Hackers exploited a flaw in it to include and execute malicious files from remote servers. Another example is the attacks on Joomla sites where similar vulnerabilities allowed remote files to be included and executed.

Step 1: Identify remote file inclusion vulnerabilities

Identifying remote file inclusion (RFI) vulnerabilities on your WordPress site is the first step to ensuring it is protected against such attacks. Here are some practical steps you can take to spot these vulnerabilities:

  • Check if anything on your site needs to be updated: Developers often release updates to patch security vulnerabilities, including RFIs. Using outdated versions of plugins and themes makes your site more susceptible to attacks exploiting such vulnerabilities. This is why we always recommend keeping your WordPress core, plugins, and themes updated.

    Need an easy way to do this? Use MalCare. It can find all vulnerabilities that exist on your site along with controls to address them. It will also give you an overview of all updates available for your site along with the option to perform those updates.
  • Conduct penetration testing on your site: Hire a security expert or use tools like nmap, sqlmap, etc. to perform penetration testing on your site. They can simulate attacks and attempt to exploit any weaknesses, including RFI vulnerabilities. This can give you a clear idea of how vulnerable your site is and what needs to be fixed.
  • Check your site’s error logs: Review your site’s error logs regularly. Look for suspicious activity such as unexpected errors or attempts to access non-existent files. This can be an early warning sign that someone is trying to exploit an RFI vulnerability.

Additionally, there are online tools and services like Acunetix, Nessus, and OpenVAS that can perform comprehensive scans of your site. They look for known RFI vulnerabilities and other security weaknesses. You can set these up to run regular scans and get reports on potential issues.

Generally speaking, it is very difficult for a site owner to stay on top of vulnerabilities that haven’t been discovered by a security researcher. Penetration testing and hiring cybersecurity companies are considerably expensive options. Therefore the best way to protect a WordPress site is to fortify it with a firewall, which will not remove vulnerabilities, but protect a site from attacks regardless of whether vulnerabilities exist on the site or not.

Step 2: Scan your WordPress site for malware

Remote file inclusion (RFI) attacks are often used to deliver malware to your WordPress site. This is why identifying them is crucial. Here are some effective ways to detect and address potential malware resulting from RFI:

  • Use a website scanner like MalCare: WordPress website scanners like MalCare can automatically scan your site for malware. MalCare looks deep into your site’s files and database to identify any suspicious code or activity. If it detects any malware, it alerts you immediately, and you can remove it in just one click. It also provides detailed reports on detected issues, helping you understand what’s wrong and take corrective measures.
Security and Firewall section on MalCare dashboard
  • Use an activity log: Activity logs are essential for monitoring what happens on your WordPress site. MalCare comes with a built-in activity log that can help you track changes and spot suspicious activities.

    On your site’s activity log, look for any unexpected changes in your files. If a new file appears out of nowhere or an existing file is modified without your knowledge, it could be a sign of an RFI attack. Also monitor user activity for unusual behavior, such as logins from unfamiliar IP addresses or admin-level actions from regular user accounts. Keep an eye on any changes to your plugins and themes as well.
  • Perform code reviews of plugins and themes: Performing manual code reviews is another way to identify malware. However, this method is highly technical and not recommended for everyone. It can be time-consuming and runs the risk of missing something critical.

    That said, if you have the technical expertise or can hire a security professional, reviewing the code can provide a thorough check for any signs of RFI exploitation.

Now there are online scanners as well, like Sucuri SiteCheck, that can surface-scan your site for vulnerabilities and malware. They can be a good first step to finding out if something is wrong with your site. However, they are not very effective as they cannot dive deep into your site’s files and database. This is why we recommend MalCare for its robust vulnerability scanning and malware redressal features.

Step 3: Remove malware rising from RFI attacks

If your WordPress site has been compromised by remote file inclusion (RFI) attacks, it’s crucial to act quickly to clean up the site and prevent further attacks. Here are the steps you should take:

1. Use a malware cleaner like MalCare

The easiest and most effective way to clean your WordPress site is by using a malware cleaner like MalCare. All you need to do is install it on your site and run a scan.

MalCare can automatically detect and remove malware from your site, in just a few clicks. It looks deep into your files and database and eliminates even the most persistent malicious code. MalCare is also fast and can clean your site within minutes, minimizing downtime and restoring your site’s integrity.

Alternatively, you can opt for manual cleanup, but this is only recommended if you are technically adept or you have the resources to hire security experts. Manual cleanup involves going through each file and database entry to find and remove malicious code, which can be time-consuming and prone to errors.

2. Update WordPress core, plugins, and themes

Make sure your WordPress core, plugins, and themes are up-to-date. Updates often include security patches that fix vulnerabilities. If the RFI vulnerability existed in a plugin or theme, updating it might resolve the issue.

However, if there are no updates available for a vulnerable plugin or theme, disable it immediately. Look for a replacement until the vulnerability is patched to avoid leaving your site exposed.

3. Change all passwords and inform users

If you detect RFI attacks on your site, change all passwords for your WordPress admin accounts, hosting accounts, and database. Inform your users to change their passwords too. Compromised passwords can be a gateway for hackers to re-infect your site.

Change WordPress Password

4. Implement login security

Boost your site’s login security to prevent unauthorized access. This means enabling security measures like two-factor authentication (2FA) and CAPTCHA. Adding a second layer of protection makes it harder for hackers to gain access even if they have a password. Moreover, adding CAPTCHA to your login forms helps prevent automated login attempts and brute-force attacks.

Implementing 2FA

5. Conduct a security audit

Perform a thorough security audit to ensure that your site is fully secure. This includes reviewing all user roles and permissions and checking for any files that might have been uploaded without your consent or knowledge.

Make sure no user has more access than they need and remove or downgrade any suspicious accounts that you see. For your peace of mind, you can connect to your site over FTP or using cPanel’s File Manager, and check the files in your uploads directory. However, if you have MalCare installed on your site, you can rest assured as it can handle this automatically.

User Accounts Review

Step 4: Post-hack checklist for remote file inclusion exploits

Experiencing a remote file inclusion (RFI) exploit can be daunting. It’s vital to restore your site and secure it against future threats.

MalCare HackCleanup Security keys Reset 2

Here’s a straightforward checklist to guide you through the post-hack process:

  • Change passwords: Change all passwords for WordPress admin, hosting accounts, database, SFTP, and any other access points. Use complex passwords with a mix of letters, numbers, and special characters. If you can, reset all user passwords and inform them about this change.
  • Use security plugins: Install and run a security plugin like MalCare. These can detect and sometimes fix malicious code. They can check critical files such as wp-config.php, .htaccess, and plugin/theme files for suspicious code.
  • Update everything: Update WordPress to the latest version. Update all your plugins and themes. Updates often include security patches. Remove any outdated, unused, or deprecated ones.
  • Restore clean backup: If you have a clean backup from before the hack, restore your site. Ensure that the backup is indeed clean to avoid reintroducing the malware.

    If you are not using any backup plugin yet, we recommend BlogVault for its easy one-click backup and restore capabilities. It also offers unlimited offsite encrypted data storage, an emergency connector to restore fully crashed sites, as well as the ability to test restores before applying them to your live site.

    Once done, check the restored site thoroughly to ensure it’s free from infections. Only use a backup to recover from an attack if the hacker has destroyed your site beyond recovery.
  • Remove search engine blacklists: Search engines like Google blacklist your site if they suspect it contains malware. As a result, users are warned when trying to access your site. Hence, it becomes crucial to get your site off Google’s blacklist.
  • Educate yourself and your users: Stay updated on WordPress security best practices and common vulnerabilities. Consider educating your users on recognizing phishing attempts and maintaining good security hygiene.

Step 5: Prevent future remote file inclusion attacks

Whether you have a brand new WordPress site or you have cleaned your existing site, protecting it from remote file inclusion (RFI) attacks is crucial for maintaining its security. Here are some effective strategies to bolster your site’s defenses:

  • Use a firewall like MalCare: Web application firewalls like MalCare provide comprehensive protection for your site. Apart from blocking attacks and preventing exploits, MalCare continually scans your site for vulnerabilities and malware. In case malware is detected, MalCare can clean it in just one click.
  • Disable file upload/inclusion options if not necessary: Limit the areas of your site where file uploads or inclusions are allowed. Only enable file upload or inclusion features when absolutely necessary. This reduces the risk surface. Also use plugins or settings that give you more control over file uploads, allowing only specific file types and vetted sources.
  • Disable URL entry in your site’s php settings: Prevent the PHP engine from automatically fetching and executing code from URLs. You can do this by adding the allow_url_include=0 and allow_url_fopen=0 conditions to your php.ini file. Disabling these settings helps block RFI attempts from including remote files.
  • Keep WordPress core, plugins, and themes updated: Regular updates are essential for security. Updates often include patches for security vulnerabilities, alongside new features and performance improvements. Ensure you update your site regularly to keep it safe and secure.
  • Use reputed and regularly maintained plugins and themes: Choose plugins and themes from reputable sources, like the WordPress repository. Trusted plugins and themes are more likely to be free from security flaws. You should also check their release notes or changelogs to ensure that they are regularly updated and maintained by their developers.
  • Restrict file permissions: Limit file permissions to minimize risks. Only grant the minimum permissions necessary for files and directories. Ensure that sensitive files like wp-config.php have restricted access.
  • Implement strong passwords and login security: Secure your login credentials. Use complex passwords that are hard to guess, and inform your users to do so too. Enable 2FA and CAPTCHA to prevent automated login attempts and add an extra layer of security.
  • Perform regular security audits: Routine audits help you catch issues early. Use tools and plugins to scan your site for vulnerabilities regularly. If you are a MalCare user, this bit is taken care of. Additionally, review user roles and permissions periodically to ensure no unnecessary access.
  • Harden your website: Take additional steps to make your site more secure. Implement security headers such as X-Content-Type-Options, X-Frame-Options, and Content-Security-Policy. Disable XML-RPC unless needed, as it can be a vector for attacks. Restrict the number of failed login attempts to prevent brute-force attacks.

Impacts of remote file inclusion attacks on your WordPress site

Remote file inclusion (RFI) attacks can have devastating effects on your WordPress site, leading to numerous security and operational issues.

What are signs that a Website has been Hacked

Here are the key consequences you might face:

  • Data theft: One of the most immediate and damaging effects of an RFI attack is data theft. Hackers can steal sensitive information such as user data, payment details, and confidential business information. This compromised data can lead to larger data breaches, harming your site’s reputation and user trust.
  • Malware distribution: RFI attacks can turn your WordPress site into a vehicle for distributing malware. Once on your site, this malware can spread to visitors’ devices, increasing the scope of the attack.
  • Site defacement: Hackers often deface your site to make a statement or as a sign of control. Defacing your site can severely damage your brand’s credibility and user trust. Users encountering a defaced site are likely to leave immediately, and some may never return.
  • Remote code execution (RCE) attacks: RFI can lead to RCE, allowing hackers to execute arbitrary code on your server. They can then install backdoors, giving them persistent access to your site even after initial cleanup. Your site might even be used to launch DDoS attacks on other sites, consuming your server resources. Moreover, hackers can create unauthorized admin accounts, further compromising your site’s security and giving them control over it.
  • Complete site takeover: In the worst-case scenario, an RFI attack can let hackers gain full control over your WordPress site, locking you out entirely. Some hackers may demand a ransom to return control, although paying a ransom is generally not advisable since it doesn’t guarantee the safety or return of your site. Recovering from a total site takeover can be lengthy and expensive, affecting your business operations and reputation.

Remote file inclusion vs Local file inclusion

While trying to understand remote file inclusion (RFI), you might have heard of local file inclusion (LFI) too. Both vulnerabilities are about including files, but the way they work is different.

AnonymousFox WordPress Hack

LFI is like cooking and bringing your own lunch to the office. The hacker has to upload the malicious files directly to your site. Once these files are there, the attacker finds a way to get the site’s server to execute them. This can be done either by exploiting existing vulnerabilities, using action commands like $_GET in the malicious file, or even through social engineering.

In contrast, RFI is like ordering takeout to your office. The hacker doesn’t need to upload files directly to your site. They just provide a URL where the malicious files are stored. The site then pulls in those files and executes them.

Final thoughts

Understanding and protecting against remote file inclusion (RFI) attacks is crucial for maintaining the security and integrity of your WordPress site. RFI vulnerabilities can lead to severe consequences, including data theft, site defacement, malware distribution, and even complete loss of control over your site. Familiarizing yourself with how RFI works is the first step in creating a robust defense against such attacks.

Use MalCare to further enhance your site’s security and ensure ongoing protection. MalCare offers comprehensive features such as real-time malware scanning and cleaning, firewall protection, and vulnerability assessments, making it a valuable asset in securing your WordPress site. Its Atomic Security firewall can proactively detect and mitigate threats, ensuring your site remains resilient against RFI attacks and other security vulnerabilities.

FAQs

What is remote file inclusion?

Remote file inclusion is a security vulnerability that allows attackers to insert a malicious file from a remote location into your website, application, or script. This can lead to unauthorized code execution, data theft, and even full control over the compromised site.

What is the difference between RFI and RCE?

Remote file inclusion (RFI) and remote code execution (RCE) are both serious security vulnerabilities, but they work differently and have distinct implications. RFI occurs when an attacker can include a file from a remote location into your website, application, or script. RCE, on the other hand, allows an attacker to execute arbitrary code on your server. This capability can result from multiple vulnerabilities, including RFI. In summary, RFI is a method of including and running remote files, which can lead to RCE if exploited effectively.

What is the difference between RFI and LFI?

Remote file inclusion (RFI) and local file inclusion (LFI) are both security vulnerabilities related to file inclusion, but they operate differently. RFI occurs when an attacker can include a file from a remote location (usually another server) into your website, application, or script. LFI, on the other hand, involves the inclusion of files that already exist on the server hosting the website.

How can we prevent RFI?

You can prevent RFI on your site by using a security plugin like MalCare, disabling unnecessary URL entry features in PHP settings, implementing a Web Application Firewall (WAF), and keeping WordPress core, plugins, and themes updated. You must also choose reputable and regularly maintained plugins and themes, restrict file permissions to the minimum necessary, enhance login security, conduct regular security audits, and harden your site.

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