Web Application Penetration Testing
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Application Security Testing
What is web application penetration testing?
Web application security focuses on protecting the systems that power modern websites, platforms, and online services. These applications often handle sensitive data, business logic, and user interactions, which makes them a frequent target for attackers.
Security weaknesses often arise from insecure code or third-party libraries that can affect application logic, authentication flows, and how users interact with the system. These issues are rarely detected by automated scanners.
Web application penetration testing aims to identify vulnerabilities that could allow an attacker to access data, bypass controls, or abuse functionality. By simulating real-world attack techniques, penetration testing helps organisations understand their true exposure and to prioritise remediation based on business risk and impact.
This type of testing is particularly important for applications exposed to the internet or used by customers, partners, or internal staff. If you’re preparing for your first assessment, our guide to scoping a web application penetration test covers what to prepare and what to expect.
Who Needs This
Who needs web application penetration testing?
Web application testing is essential for any organisation whose applications handle sensitive data, business logic, or user interactions that are exposed to the internet or used by customers, partners, or internal staff.
SaaS and platform providers
Applications handling customer data or multi-tenant environments carry a high blast radius if compromised. Authentication flaws and access control weaknesses are routinely found in SaaS platforms.
E-commerce businesses
Payment flows, account management, and order logic are all high-value targets. Business logic vulnerabilities in checkout and pricing are common findings that automated scanners miss entirely.
Financial services
Online portals, banking apps, and trading platforms require testing across all authenticated roles. Privilege escalation and insecure direct object references are frequently critical in these environments.
Healthcare organisations
Patient data accessed through web interfaces is subject to strict regulatory requirements. Session management weaknesses and insufficient access controls are common findings.
Startups with new deployments
Pre-launch is the right time to test. Catching authentication flaws, injection vulnerabilities, and API weaknesses before go-live is significantly less expensive than post-breach remediation.
Applications processing sensitive data
Any application handling personal data, financial records, or confidential business information presents a meaningful risk profile that warrants regular, manual penetration testing.
Our Pentest Methodology
OWASP aligned testing methodology
Our methodology is aligned with the OWASP Testing Guide and OWASP Top 10, combining manual testing with intelligence-driven discovery to uncover vulnerabilities that automated scanners miss. Each assessment is tailored to your application’s technology stack, authentication model, and business logic.
Authentication & Authorisation
MFA bypass, password policy weaknesses, session fixation, privilege escalation , and insecure direct object references (IDOR) .
Injection Vulnerabilities
SQL injection , command injection, LDAP injection, XML injection, and server-side template injection across all input vectors.
Business Logic Flaws
Race conditions, workflow bypass, price manipulation, payment logic abuse, and application-specific vulnerabilities that automated scanners cannot detect.
Session Management
Session hijacking , cookie security, token handling, timeout configurations, and cross-site request forgery (CSRF) protections.
API Security
REST and GraphQL API testing, rate limiting, authentication mechanisms, data validation, and API-specific vulnerabilities aligned with the OWASP API Top 10.
Client-Side Security
Cross-site scripting (XSS) , DOM-based vulnerabilities, insecure JavaScript libraries, and client-side logic manipulation.
Access Control
Horizontal and vertical privilege escalation, forced browsing, missing function-level access controls, and role-based access bypass.
Infrastructure & Configuration
Security headers, TLS/SSL configuration, subdomain takeover risks, and server misconfigurations that impact application security.
Pricing
From £2,700
for web application penetration testing
Not sure where your application fits? A 30-minute scoping call is free and gets you a fixed written quote.
No obligation · Strictly confidential · Quote within one business day
Pricing Examples
| Standard web app (unauthenticated or low complexity) | £2,700 - £4,500 |
| Medium complexity SaaS (multiple roles) | £4,500 - £6,300 |
| Complex enterprise platform | £6,300+ |
What's Included
- Fixed-price proposal within one business day
- Manual, consultant-led testing. Not automated scans
- Report within 2 business days of testing completion
- Free focused-retesting included to verify remediation
- No obligation quote, all enquiries are fully confidential
Indicative ranges only. Your exact price is confirmed after a short scoping conversation - see full service pricing .
Key Deliverables
What's included in the assessment?
Every Exploitr engagement is delivered as a defined set of outputs designed to support both technical remediation and executive-level decision-making.
Executive Report
A non-technical summary of findings with risk ratings and recommendations suitable for board and senior management stakeholders.
Technical Report
A detailed report covering each vulnerability with reproduction steps, severity scoring, remediation guidance, and mappings to CVE, CVSS, and MITRE ATT&CK where applicable.
Debrief Session
An offer of a debrief call to walk through findings, discuss remediation priorities, and answer questions from both technical and executive stakeholders.
Free Retesting
Complimentary focused retesting of any remediated vulnerabilities to verify that identified issues have been properly resolved.
Attack Surface Center Access
Complimentary access to our Attack Surface Center ASM platform to review, track, and collaboratively remediate findings in real time throughout and beyond the engagement.
Consultant-led Testing
All testing is consultant-led by in-house staff. Your consultant works with you from scoping through to debrief. Nothing is outsourced or subcontracted.
Common Questions
Web application penetration testing - frequently asked questions
Most web application pentests take 3-6 days depending on the scope and complexity of the application. Testing can be performed against development, staging, or production environments.
Reports are delivered within 2 business days of testing completion. For a full walkthrough of what happens from scope agreement through to report delivery, see what to expect during a web application pentest .
Whilst penetration testing comes with an inherent risk, we use safe testing techniques and coordinate with your team to minimise any potential impact. Testing is typically performed in non-production environments, though production testing can be conducted with appropriate safeguards in place.
Yes, API testing is included when APIs are part of the application’s functionality. The scope is based on the application’s functionality, not the number of endpoints. For API-only applications, we offer dedicated API penetration testing .
We test both as an anonymous attacker and as authenticated users across different privilege levels to identify privilege escalation and access control issues.
If your application offers the ability for users to self-register, we also focus on targeted vulnerability discovery of this workflow. If your application doesn’t offer self-registration, then we would ask you to provide us with sample user credentials in order to perform authenticated user testing.
Yes, we regularly test React, Angular, Vue applications and other modern frameworks, including their API backends and client-side logic.
We use automated tools to enhance discovery efficiency, but testing is entirely manually-led and intelligence-driven. Every finding is validated and exploited by our consultants. We do not run a vulnerability scan and call it a day.
Yes, we can test web applications regardless of the underlying platform or technology stack. This includes CMS-based sites such as WordPress and WooCommerce, e-commerce platforms like Shopify, custom-built applications in any language or framework (PHP, Python, Node.js, .NET, Ruby on Rails, etc.), and SaaS platforms built on modern stacks like React, Angular, or Vue with API backends.
The approach is tailored to the platform:
- For WordPress sites, we assess plugin vulnerabilities, theme security, authentication controls, and common CMS misconfigurations.
- For Shopify, testing focuses on custom app logic, third-party integrations, and checkout flows.
- For custom-built applications, we conduct a thorough assessment of the full application surface, looking at the authentication, authorisation, business logic, data handling, and API security.
If you’re unsure of what you may need for your website or application pentest, get in touch. We’re happy to discuss your environment during a brief scoping call.
Annual testing at minimum, with additional testing after major releases, significant feature additions, or architectural changes. Many organisations benefit from continuous testing through our Pentest as a Service offering .
Ready to secure your web application?
Get a fixed-price quote within 24 hours. Our team will review your application’s scope and provide a tailored testing proposal that fits your timeline and budget.