How to Check a Website for Viruses and Malware: A Complete Security Guide

Website security is not optional — it is a fundamental requirement for any online presence. Whether you run a personal blog, an e-commerce store, or a corporate platform, malware infections can destroy your reputation, compromise user data, and tank your search engine rankings overnight. This comprehensive guide walks you through every method available to detect, analyze, and eliminate viruses and malware from your website, so you can keep your platform safe, trusted, and fully operational.

What Are Website Viruses and Malware?

Website malware refers to any malicious software intentionally injected into a website's files, database, or server environment. Unlike desktop viruses, website-based malware often operates silently in the background — stealing data, redirecting visitors, or turning your server into a spam relay without any obvious signs.

Understanding the most common types of malware is the first step toward effective protection:

• Backdoors — Hidden entry points that allow attackers to access your server remotely, even after you've changed passwords or patched vulnerabilities.
• Trojan Horses — Malicious scripts disguised as legitimate plugins, themes, or software packages that execute harmful code once installed.
• Ransomware — Encrypts your website files and demands payment in exchange for the decryption key, effectively holding your site hostage.
• Adware — Injects unauthorized advertisements into your web pages, generating revenue for attackers while degrading user experience.
• Phishing Pages — Hidden pages created on your server to harvest login credentials or financial information from unsuspecting visitors.
• SEO Spam — Malicious code that injects hidden links or keyword-stuffed content to manipulate search rankings for third-party sites.
• Cryptominers — Scripts that hijack your server's CPU resources to mine cryptocurrency, causing severe performance degradation.

Each of these threats can cause lasting damage to your site's integrity, SEO performance, and visitor trust. Early detection is critical.

Warning Signs That Your Website May Be Infected

Before diving into scanning tools and manual checks, you should know the red flags that often indicate a malware infection is already underway:

• Unexpected content changes — New pages, posts, or links appearing that you did not create.
• Suspicious redirects — Visitors are being sent to unrelated or malicious third-party websites.
• Browser security warnings — Google Chrome, Firefox, or Safari display a "This site may be hacked" or "Deceptive site ahead" warning.
• Google Search Console alerts — Google notifies you of security issues or manual actions in your account.
• Blacklisting — Your domain appears on spam or malware blacklists, causing email delivery failures or search ranking drops.
• Degraded performance — Unexplained slowdowns, high CPU usage, or unusual server load spikes.
• Hosting provider suspension — Your hosting account is suspended due to malicious activity detected on your server.

If you notice any of these symptoms, treat it as an emergency and begin scanning immediately.

Method 1: Using Online Security Scanners

Online security scanners are the fastest way to get an initial assessment of your website's health. They analyze your publicly accessible pages for known malware signatures, blacklist status, and common vulnerabilities.

Step 1: Choose the Right Scanner

Each tool has different strengths. Use multiple scanners for the most thorough results:

Step 2: Enter Your Website URL

Navigate to your chosen scanner's website and enter your full domain URL (e.g., https://www.yourdomain.com) into the input field. Make sure to include the correct protocol (https:// or http://) for accurate results.

Step 3: Initiate the Scan

Click the Scan, Check, or Analyze button to start the process. Depending on the tool and your site's size, the scan may take anywhere from a few seconds to several minutes.

Step 4: Interpret the Results

Once the scan completes, carefully review the output. Pay close attention to:

• Malware Detected — Any identified malicious code, injected scripts, or suspicious files.
• Blacklist Status — Whether your domain appears on Google, McAfee, Spamhaus, or other major blacklists.
• Outdated Software — Flags for outdated CMS versions, plugins, or themes with known vulnerabilities.
• SSL/TLS Issues — Weak cipher suites, expired certificates, or misconfigured HTTPS settings.

> Pro Tip: Online scanners only analyze your publicly visible pages. They cannot access server-side files or database content. Always follow up with a server-level scan for complete coverage.

Method 2: Manual File and Code Inspection

For a deeper investigation, manual inspection of your server files is essential. This approach requires access to your hosting environment and a basic understanding of web file structures.

Step 1: Access Your Server Files

Connect to your server using one of the following methods:

• FTP/SFTP Client — Use FileZilla or Cyberduck to browse your file system remotely.
• Hosting Control Panel — Access the File Manager through cPanel, Plesk, or a similar panel. If you're looking for a managed environment with intuitive control panel access, VPS with cPanel provides a powerful and user-friendly solution.
• SSH Terminal — For advanced users, SSH access provides the most powerful inspection capabilities.

Step 2: Identify Recently Modified Files

Attackers typically modify existing files or add new ones during an infection. Use the following SSH command to list files modified in the last 7 days:

find /var/www/html -type f -mtime -7

Adjust the path to match your web root directory. Any recently modified core files (especially PHP files in WordPress's wp-includes or wp-admin directories) that you did not intentionally change should be treated as suspicious.

Step 3: Search for Common Malware Patterns

Use grep to search for known malicious code patterns across your entire web directory:

# Search for base64 encoded payloads (common obfuscation technique)
grep -r "base64_decode" /var/www/html --include="*.php"

# Search for eval() with encoded content
grep -r "eval(base64" /var/www/html --include="*.php"

# Search for common backdoor functions
grep -r "exec|system|passthru|shell_exec" /var/www/html --include="*.php"

# Search for hidden iframe injections
grep -r "<iframe" /var/www/html --include="*.html" --include="*.php"

Step 4: Review HTML and PHP Source Files

Open your core template files — particularly header.php, footer.php, index.php, and .htaccess — and look for:

• Obfuscated code — Long strings of seemingly random characters, often encoded in base64 or hexadecimal.
• Hidden iframes — <iframe> tags pointing to external domains, often with display:none styling.
• Unauthorized redirects — PHP header() calls or JavaScript window.location redirects to unknown URLs.
• Suspicious eval() calls — Dynamic code execution that processes encoded or encrypted payloads.

Step 5: Check Your .htaccess File

The .htaccess file is a frequent target for malware injection. Open it and verify that it contains only your expected configuration. Look for unexpected RewriteRule directives that redirect traffic to external sites, especially rules that target mobile users or search engine crawlers specifically.

Step 6: Inspect Your Database

For CMS platforms like WordPress, malware is frequently stored in the database. Use phpMyAdmin or a direct MySQL query to search for suspicious content:

SELECT * FROM wp_posts WHERE post_content LIKE '%base64%';
SELECT * FROM wp_options WHERE option_value LIKE '%eval(%';

Method 3: Server-Level Antivirus Scanning

For the most thorough malware detection, run a dedicated antivirus scanner directly on your server. This is particularly important if you have VPS Hosting or a Dedicated Server, where you have root access to install and run security tools.

ClamAV — Open Source Antivirus for Linux

ClamAV is the most widely used open-source antivirus engine for Linux servers. Here's how to install and use it:

Install ClamAV on Ubuntu/Debian:

sudo apt update
sudo apt install clamav clamav-daemon -y
sudo systemctl stop clamav-freshclam
sudo freshclam
sudo systemctl start clamav-freshclam

Run a Full Scan of Your Web Directory:

sudo clamscan -r /var/www/html --infected --remove --log=/var/log/clamav_scan.log

-r — Recursive scan of all subdirectories
--infected — Only display infected files
--remove — Automatically remove detected threats
--log — Save results to a log file for review

Review the Scan Log:
cat /var/log/clamav_scan.log
Maldet (Linux Malware Detect)
Linux Malware Detect (LMD) is specifically designed to detect threats commonly found in shared hosting environments and is highly effective against web-based malware:
# Download and install LMD
wget http://www.rfxn.com/downloads/maldetect-current.tar.gz
tar -xzf maldetect-current.tar.gz
cd maldetect-*/
sudo ./install.sh

# Run a scan
sudo maldet -a /var/www/html
Method 4: CMS-Specific Security Plugins
If your website runs on a content management system, dedicated security plugins provide continuous, automated protection without requiring manual intervention.
WordPress Security

Wordfence Security — Provides a Web Application Firewall (WAF), real-time malware scanner, login security, and traffic monitoring. The free version is highly capable for most sites.
Sucuri Security — Offers file integrity monitoring, security activity auditing, and post-hack security actions.
MalCare — Features one-click malware removal and deep scanning that doesn't impact server performance.
iThemes Security — Focuses on hardening WordPress against brute force attacks and unauthorized access.

Joomla Security

RSFirewall! — Comprehensive security suite with system check and firewall capabilities.
Akeeba Admin Tools — Provides a WAF, security hardening, and .htaccess optimization.

Drupal Security

Security Review — Automated checks for common security misconfigurations.
Paranoia — Restricts PHP execution in certain directories to prevent code injection.

Method 5: Monitoring Google Search Console
Google Search Console is a free and invaluable resource for detecting security issues that Google has already identified on your site.

Log in to Google Search Console.
Navigate to Security & Manual Actions → Security Issues.
Review any flagged issues, including hacked content, malware, or deceptive pages.
After cleaning your site, use the Request Review feature to ask Google to re-evaluate your site and remove any warnings.

What to Do If Malware Is Found
Discovering malware on your website requires immediate, systematic action. Follow this response plan:
1. Take Your Site Offline Temporarily
Put your site into maintenance mode to prevent further damage to visitors and stop the spread of malware. This also signals to search engines that you are actively addressing the issue.
2. Change All Credentials Immediately

FTP/SFTP passwords
Hosting control panel password
CMS admin passwords
Database passwords
SSH keys

3. Restore from a Clean Backup
If you have a recent backup from before the infection, restoring it is often the fastest path to a clean site. This is why regular, automated backups are non-negotiable. AlexHost's VPS Hosting plans include backup options to ensure your data is always recoverable.
4. Manually Remove Malicious Code
If a clean backup is not available, manually remove all identified malicious code. Replace core CMS files with fresh downloads from the official source and audit every custom file individually.
5. Identify and Patch the Entry Point
Cleaning the malware without fixing the vulnerability that allowed the infection is pointless — attackers will simply re-infect your site. Common entry points include:

Outdated plugins or themes with known vulnerabilities
Weak or reused passwords
Compromised FTP credentials
Vulnerable server software (PHP, Apache, Nginx)
Insecure file permissions

6. Request Blacklist Removal
If your site was blacklisted by Google or other services, submit a review request after cleaning:

Google — Use Google Search Console's Security Issues section.
McAfee SiteAdvisor — Submit via the McAfee website.
Spamhaus — Use the Spamhaus removal request form.

Proactive Security Best Practices
Prevention is always more effective than remediation. Implement these practices to significantly reduce your attack surface:
Keep Everything Updated
Outdated software is the single most common cause of website infections. Keep your CMS core, plugins, themes, and server software updated at all times. Enable automatic updates where possible.
Use Strong, Unique Passwords and 2FA
Enforce strong password policies for all accounts associated with your website. Enable two-factor authentication (2FA) on your CMS admin panel, hosting control panel, and any other access points.
Implement Correct File Permissions
Incorrect file permissions are a critical security risk. Use the following as a baseline:
# Directories: 755
find /var/www/html -type d -exec chmod 755 {} ;

# Files: 644
find /var/www/html -type f -exec chmod 644 {} ;

# wp-config.php (WordPress): 400 or 440
chmod 400 /var/www/html/wp-config.php
Install and Configure a Web Application Firewall (WAF)
A WAF filters malicious traffic before it reaches your application. Options include Cloudflare (cloud-based), ModSecurity (server-level), or plugin-based WAFs like Wordfence.
Secure Your SSL/TLS Configuration
An active, properly configured SSL certificate is essential for both security and user trust. It encrypts data in transit and is a confirmed Google ranking factor. You can easily secure your domain with an SSL Certificate to protect your visitors and boost your site's credibility.
Schedule Regular Automated Backups
Configure automated daily or weekly backups stored in a separate location from your primary server. This ensures you always have a clean restore point available.
Harden Your Server Configuration
If you manage your own server, apply these hardening measures:

Disable unused PHP functions (exec, system, passthru) in php.ini

Monitor Your Domain and Email Reputation

Malware infections can compromise your email sending reputation. If you rely on professional email communication, consider using a dedicated Email Hosting service to keep your email infrastructure isolated and secure.

Choosing the Right Hosting Environment for Security

Your hosting environment plays a fundamental role in your website's security posture. Not all hosting solutions offer the same level of control and protection.

• Shared Web Hosting — Ideal for small websites with low traffic. AlexHost's shared hosting plans include essential security features and are managed to ensure a secure environment for your files.
• VPS Hosting — Provides dedicated resources and root access, allowing you to implement custom security configurations, run server-level antivirus tools, and control every aspect of your environment. Highly recommended for business websites.
• Dedicated Servers — The highest level of isolation and performance. With a dedicated server, your resources are never shared with other users, eliminating the risk of cross-contamination from neighboring accounts. AlexHost's dedicated servers include DDoS protection and NVMe storage for maximum reliability.

For high-performance applications requiring GPU resources, GPU Hosting offers powerful infrastructure with the same commitment to security and uptime.

Quick Reference: Website Security Checklist

Use this checklist to maintain a consistently secure website:

• [ ] Run an online malware scan (Sucuri, VirusTotal) weekly
• [ ] Review Google Search Console for security alerts monthly
• [ ] Update CMS, plugins, and themes immediately upon release
• [ ] Verify automated backups are running and restorable
• [ ] Audit file permissions quarterly
• [ ] Review server access logs for suspicious activity monthly
• [ ] Confirm SSL certificate is valid and properly configured
• [ ] Test all admin passwords for strength and uniqueness
• [ ] Verify WAF is active and rules are current
• [ ] Check domain blacklist status monthly

Conclusion

Website security is an ongoing process, not a one-time task. Malware threats evolve constantly, and attackers continuously discover new vulnerabilities to exploit. By combining automated online scanners, manual file inspection, server-level antivirus tools, and proactive hardening measures, you create multiple layers of defense that make your website significantly harder to compromise.

The key takeaways from this guide are clear: scan regularly, update everything, back up consistently, and choose a hosting environment that supports your security goals. Whether you're running a small blog on Shared Web Hosting or managing a high-traffic application on a Dedicated Server, AlexHost provides the infrastructure, performance, and protection you need to keep your online presence secure and trusted.

Start your security audit today — because the best time to find malware is before your visitors do.