Website security matters. It’s a vital foundation in protecting sensitive data, maintaining customer trust, and ensuring compliance for businesses of every size.
Web applications are prime targets for hackers because of their exposure to the internet. If your customers can access your website, so can attackers. Security problems can stem from anything, from misconfigured servers, insecure APIs, to overlooked vulnerabilities, leaving your organisation exposed to manipulation, disruption, or data theft.
With the recent surge in high-profile cyberattacks, including the incident that took M&S’s website offline for days and the similar attack on Harrods, it’s clear that businesses face growing pressure to prioritise their website security.
But there’s no need to panic: there is a way to stay ahead of malicious hackers and check website vulnerability in a standardised and effective manner.
By adopting proactive security testing methods, including external penetration testing, organisations can uncover hidden risks early, patch weaknesses quickly, and strengthen their defences, preventing threats long before they become damaging incidents.
What Is Web Application Testing?
Penetration testing involves a controlled simulation of real-world attacks, performed by dedicated security professionals. Using ethical hacking techniques, pentesters can assess and identify website vulnerabilities that may lead to compromised application data and disruption of web application functionality, which can lead to reputational damage and consumer trust.
A web application penetration test provides greater assurance than standard web security scanners by doing a more in-depth analysis of your attack surface, which helps enable more efficient and effective remediation.
Web application pentesting is great for:
- Detecting exploitable flaws before attackers do
- Verifying patching and security configurations (and highlighting misconfigurations)
- Supporting compliance regulations and risk management
Web Application Pentesting Process
What actually happens during a web application pentest? The typical process includes several stages- reconnaissance, scanning, testing, and reporting, which collectively help to build an accurate overview of your security posture.
The reconnaissance phase involves testers gathering as much information as possible about your target web application. Then, during the scanning phase, testing teams use automation to enumerate and scan for potential vulnerabilities. These vulnerabilities are then analysed, providing testers with the necessary insights to simulate an attack on the scoped areas.
This way, pentesters can demonstrate the damage that attackers could cause, reporting back on the range of ways they have breached your website’s security in a detailed pentest report.
Vendors such as OnSecurity provide these findings in real-time, empowering you to swiftly close your vulnerability window and minimise the risk of these threats developing.
Ways to Check Website Security
Vulnerability Scanners
Between web application pentests, your organisation may want to invest in ways to monitor your web app security. Website vulnerability scanners are an affordable and continuous addition to web application pentesting, scanning your website for known vulnerabilities, outdated software, or configuration issues.
They are excellent at providing additional eyes on your security posture between tests, though they should not be used as a complete replacement for your pentesting programme.
Manual security testing
Manual security testing is an essential foundation for securing any web application. More thorough than vulnerability scanners, manual security testing relies primarily on human-led analysis to dive deeper and evaluate critical vulnerabilities.
Manual security and pentesting are essential for uncovering complex, business-logic-based vulnerabilities in web applications.
Security audits and code reviews
It’s important that alongside these ongoing security reviews, your DevOps team regularly assesses source code and your web app environment for potential risks to ensure they are properly secured.
It’s always best practice to ensure secure development procedures are followed from the beginning. Regularly reviewing these, especially when there are significant changes within your business, can help determine where your dev team should focus next on improving code security, and can help identify areas requiring more extensive security review.
Ongoing monitoring and maintenance
Of course, ongoing monitoring and maintenance remain key in proactively responding to security risks. Some pentest providers, such as OnSecurity, offer continuous assurance through automated scanning and threat intelligence as part of your manual testing programme. These monitoring tools can alert you to suspicious activity or configuration changes, keeping you one step ahead of malicious activity and providing ongoing security oversight.
Common Website Security Issues Uncovered by Pentesting
With new vulnerabilities constantly emerging and threat actors leveraging AI to launch large-scale attacks, it’s no surprise that your website is often the primary target of these malicious activities.
Some of the most common vulnerabilities uncovered during web application penetration testing include:
- Outdated software and plugins – Leaving known exploits unpatched.
- SQL injection – Allowing attackers to manipulate database queries through insecure input fields.
- Cross-site scripting (XSS) – Enabling command injection of malicious scripts into user browsers.
- Weak authentication – Poor password policies, lack of MFA, and vulnerable login forms.
- Misconfigured servers – Open ports, default credentials, and exposed sensitive files.
Even small vulnerabilities can lead to major data breaches if left unaddressed. Regular security checks and scheduled scans provide essential threat intelligence that can minimise the risk of being victimised by potential weaknesses within your web applications.
Best Practices for Ongoing Website Security
Website security isn’t a one-time project. It requires ongoing vigilance, effective response plans, and the support of security tools to truly achieve a website resilient against emerging threats. For long-term, 360-degree cybersecurity protection, we recommend:
- Schedule regular web application **testing to identify new vulnerabilities.
- Maintain a vulnerability management program with timely patching.
- Educate developers and employees on secure coding and cybersecurity awareness.
- Back up data frequently and use encryption for sensitive information.
By supplementing manual pentesting with automated vulnerability scanning, businesses can build strong defences and achieve excellent security hygiene.
Be proactive in securing your web applications with OnSecurity’s AI-enhanced penetration testing platform, which combines the expertise of our manual testers with continuous automated security scanning for cyber defence that never sleeps.
