Lessons from the Field: Securing WordPress-based Online Store
- Evo-user
- Apr 16
- 9 min read
Luxury eCommerce platforms face unique challenges in today’s digital landscape, where the security of payment transactions and customer data is paramount. For an online store dealing in high-end accessories like perfumes, clutches, and belts, the stakes are even higher—any breach can result in significant business and reputation loss.
Recently, our team conducted a comprehensive security assessment for a WordPress-based luxury eCommerce site. The client’s goals were clear: safeguard sensitive customer and transaction data, eliminate business logic issues, and ensure the webstore's architecture was robust and free from web application security flaws. Using industry-recognized frameworks like the OWASP Top 10:2021 and CWE, we meticulously mapped out vulnerabilities and provided actionable insights for improving the platform's security posture.
This blog shares key findings from that assessment, offering lessons on common vulnerabilities in WordPress-based eCommerce sites and practical measures to address them.
Wordpress Security Assessment - Key Findings
During the security assessment, our team uncovered several critical vulnerabilities in the WordPress-based eCommerce store that could potentially compromise customer data, payment transactions, and the overall business integrity. Below are the key issues identified:
Stored Cross-Site Scripting (Type 2 XSS) in Outdated Plugin
One of the most significant findings was a vulnerability in the Slider Revolution plugin for WordPress. This plugin, used extensively across WordPress sites, was found to be susceptible to Stored Cross-Site Scripting via SVG file uploads in versions up to 6.7.18. Insufficient input sanitization and output escaping allowed authenticated attackers with Author-level access or higher to inject arbitrary web scripts that would execute whenever a user accessed the SVG file.
Malicious SVG File Executes XSS Payload, Triggering Unauthorized Notification Prompt. Missing Rate Limiting on Coupon Code Parameters
The application lacked rate-limiting mechanisms for coupon code parameters, leaving it vulnerable to automated brute-force attacks. Malicious actors could exploit valid coupon codes or launch attacks on user accounts, leading to resource exhaustion and revenue loss.
Missing Input Validation / Improper Input Length
A lack of proper input validation was identified, allowing users to input random data into the system. This oversight resulted in database inflation, which could degrade performance and exhaust server resources.
Missing Functional Level Access Control
Our assessment uncovered a serious flaw in functional-level access control. By manipulating email addresses, User B was able to access coupons belonging to User A. This vulnerability posed a significant risk to the business, potentially leading to revenue loss.
Outdated and Vulnerable JavaScript Libraries
The application utilized outdated JavaScript libraries, some of which had known vulnerabilities. This posed risks for exploitation by attackers leveraging these weaknesses.
Weak Password Policy
While password strength was enforced through frontend validation via JavaScript, there was no equivalent backend validation in place, leaving the authentication mechanism vulnerable.
Username Enumeration
Username enumeration was possible through specific application endpoints, potentially allowing attackers to target user accounts with brute-force login attempts.
Missing Essential Security Headers
The application lacked key security headers, which are vital for preventing attacks like clickjacking, content sniffing, and cross-site scripting.
Absence of CAPTCHA Mechanism
Crucial parts of the application, both pre-login and post-login, lacked any CAPTCHA mechanism. This absence increased the risk of automated attacks, including brute-force attempts, which could compromise user accounts or overload system resources.
Technical Insights
Our security assessment was conducted using a combination of tools and manual techniques to ensure comprehensive results. While automated scanners and tools helped us streamline repetitive and resource-intensive tasks, the true value of the assessment lay in our manual efforts, which allowed us to identify nuanced vulnerabilities that might have been overlooked by automated methods.
Tools Used
Web Browsers: Firefox and Chrome for initial observations and behavior analysis.
Scanners: ZAP and Burp Suite for intercepting and analyzing application traffic, identifying vulnerabilities, and simulating attacks.
Directory Enumeration Tools: Gobuster, FFUF, and Dirbuster for detecting hidden directories and files within the application.
Technology Profiling: Wappalyzer for understanding the application's tech stack, and WPScan for WordPress-specific vulnerability scanning.
Network & Infrastructure Analysis: Nmap for port scanning and network profiling and online tools like shodan & censys.
Manual Assessments: These formed the backbone of the evaluation. Manual testing not only provided deeper insights but also helped differentiate between real vulnerabilities and false positives generated by automated tools.
Challenges Faced
The application’s protections, including Cloudflare and Wordfence Security, frequently blocked our individual IP addresses during the assessment. These mechanisms restricted our speed and required additional coordination to continue our work. However, the development team provided exceptional support throughout the process, unblocking our IPs when necessary and ensuring the assessment progressed smoothly.
Value of Manual Assessments
While automated tools are vital for efficiency, they have inherent limitations—false positives, misinterpretation of application-specific behaviors, and a lack of context in certain scenarios. Manual assessments allowed us to uncover vulnerabilities such as functional-level access control issues and weak backend validation mechanisms that were not flagged by the tools. This hands-on approach was instrumental in delivering precise and actionable results.
Findings, Recommendations and Resolutions
Following our assessment, we provided a comprehensive list of recommendations to the client to address vulnerabilities and fortify the security of their WordPress-based eCommerce platform.
Immediate Actions
Stored XSS (WordPress Plugin RevSlider v6.7.18) and Other Plugin-Related Vulnerabilities:
What: The Slider Revolution plugin was identified as vulnerable to Stored Cross-Site Scripting (XSS). This issue occurs when untrusted input, such as malicious scripts, is stored on the server and executed whenever a user accesses it.
Why: Exploiting such vulnerabilities can allow attackers to hijack user sessions, steal sensitive information, or manipulate content displayed to users.
How:
Update all known vulnerable plugins to the latest versions to patch any security flaws.
Implement additional backend checks to validate image MIME types and enforce strict type checking. Allow only specific formats, such as `.jpg` or `.png`, and block other types (e.g., `.svg`).
Restrict permissions for image uploads to specific, trusted user accounts to limit exposure.
Security Headers
What: Key security headers were missing from the application's response. These headers are essential for defending against various common attacks.
Why: Security headers like HSTS, CSP, and X-Frame-Options reduce the attack surface, prevent content injection, and protect against clickjacking.
How:
HSTS (HTTP Strict Transport Security): Enforce HTTPS to ensure secure communication.
Content-Security-Policy (CSP): Restrict allowed sources for scripts, styles, and media to reduce the risk of injection attacks.
X-Frame-Options: Prevent clickjacking by disallowing the application from being loaded in an iframe.
X-Content-Type-Options: Protect against MIME-sniffing by forcing the browser to respect declared content types.
Rate Limiting and CAPTCHA Implementation
What: The application lacked rate-limiting mechanisms and CAPTCHA integration, leaving critical forms vulnerable to automated attacks.
Why: Without these defenses, attackers could perform brute-force attacks to exploit coupon codes, compromise accounts, or overload server resources.
How:
Apply strict rate-limiting on all identified critical forms (e.g., login, signup, coupon code input).
Combine rate-limiting with CAPTCHA challenges to differentiate between legitimate users and bots.
Username Enumeration
What: Specific endpoints exposed valid usernames through error messages during login or signup attempts.
Why: This vulnerability allows attackers to identify valid usernames, enabling targeted brute-force or phishing attacks.
How:
Replace detailed error messages with generic ones (e.g., "Invalid credentials" instead of "Invalid username").
Ensure all API endpoints follow this approach as well.
Password Policy
What: Password strength was only enforced through frontend validation using JavaScript, without corresponding backend validation.
Why: Frontend validation alone can be bypassed by malicious users, resulting in weak or predictable passwords that compromise account security.
How:
Enforce strong password policies at the backend by setting minimum and maximum password lengths, complexity rules (e.g., inclusion of uppercase, lowercase, numbers, and special characters), and preventing common or previously breached passwords.
Input Validation
What: The application lacked proper input validation, enabling users to input arbitrary data that could lead to injection attacks or resource exhaustion.
Why: Robust input validation prevents attackers from exploiting application functionality to manipulate databases or execute malicious code.
How:
Implement validation mechanisms at both the frontend and backend for all user inputs.
Use allow-lists (accepted input formats) where applicable and limit input lengths to prevent database inflation.
Server Hardening
What: Server banners exposed unnecessary details about the web server’s version, and the server was not updated regularly.
Why: Exposed server information provides attackers with insights into potential vulnerabilities.
How:
Suppress the server banner in configuration settings to obscure server details.
Regularly update the server software to patch known vulnerabilities and ensure secure operations.
Long-Term Strategies
Establish a Patch Management Program
Why: Keeping plugins, themes, and server components up-to-date is critical for eliminating vulnerabilities as they emerge.
How: Set up a structured patch management process to test and deploy updates consistently without disrupting operations.
Web Application Monitoring
Why: Proactive monitoring helps detect and respond to malicious activities before they escalate.
How: Use tools and techniques to monitor application traffic, track suspicious behavior, and analyze system logs for potential anomalies.
Secure Development Practices
Why: Secure coding practices mitigate vulnerabilities during the development phase itself, reducing remediation efforts later.
How: Provide ongoing training to the development team on secure coding principles and conduct code reviews to identify potential issues.
User Awareness
Why: End users are a critical line of defense; informed customers are less likely to fall victim to phishing or social engineering attacks.
How: Educate users on recognizing suspicious activities, creating strong passwords, and securing their accounts.
Periodic Web Application Security Assessments
Why: Cybersecurity threats evolve constantly, so periodic reviews ensure the application remains resilient against emerging risks.
How: Schedule regular security assessments to identify and fix vulnerabilities, adapting the application’s security measures over time.
Our Perspective
WordPress has undergone a remarkable transformation from its humble beginnings as a blogging platform to a highly customizable all-in-one solution. Today, it powers millions of websites across industries, including complex eCommerce stores. While this evolution brings versatility and functionality, it also introduces unique security challenges—especially when outdated plugins and limited security awareness among developers come into play.
During our assessment of a WordPress-based eCommerce platform, the most striking observations were:
Outdated Plugins: The presence of plugins with known vulnerabilities, like the Slider Revolution plugin, posed significant risks. Plugins are often a double-edged sword, enhancing functionality but also introducing vulnerabilities when not regularly updated.
Limited Security Awareness: The development team had a narrow understanding of web application security, focusing predominantly on SQL Injection (SQLi) and Cross-Site Scripting (XSS). This limited knowledge excluded broader issues like business logic flaws, functional-level access control, and the principles outlined in the OWASP Top 10.
The key takeaway we aim to highlight is the critical need for development teams and developers to invest time in understanding web application risks. Using resources like the OWASP Top 10 is invaluable for gaining insight into both common vulnerabilities and nuanced issues that can threaten business objectives. Application security requires a broader perspective—going beyond basic attack types and diving into the context-driven nature of securing complex applications.
One misconception about web application security we often encounter is the reliance on automated tools like ZAP, BurpSuite, or Acunetix for security assessments. While these tools are powerful and efficient, they are not infallible. Automated scanners may produce limited results or false positives and often fail to identify vulnerabilities unique to the application’s context. Manual verification by experienced testers is what truly brings value to assessments, uncovering deeper issues that machines simply cannot detect.
Lastly, it’s important for developers and clients to recognize that application security can be intricate and requires a contextual understanding of how the application functions and supports business use cases. As penetration testers, it’s our responsibility to evaluate applications holistically—combining technical rigor with business insights to offer security advice that aligns with the client’s goals. By addressing vulnerabilities proactively, clients can secure their applications while enabling uninterrupted business operations.
Conclusion
Securing a WordPress-based eCommerce platform requires more than just surface-level analysis. Through our comprehensive assessment, it became evident that a combination of outdated plugins, lack of security awareness, and insufficient safeguards can expose even sophisticated platforms to significant risks. However, these vulnerabilities are not insurmountable.
By addressing immediate issues such as Stored XSS vulnerabilities, missing security headers, and weak authentication mechanisms, along with implementing long-term strategies like adopting secure development practices and periodic security assessments, businesses can greatly enhance the security of their web applications.
One key lesson learned is that application security goes beyond the tools—it demands a contextual understanding of the platform, its users, and its business logic. Manual assessments conducted by experienced testers continue to be invaluable in identifying nuanced issues that automated tools often overlook.
Ultimately, security is an ongoing journey, not a one-time destination. As technology evolves, so do the threats, making continuous monitoring and proactive measures essential for safeguarding customer trust and business reputation. By investing in security, organizations not only protect their data but also ensure sustainable growth in today’s digital-first economy.
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