Web Application Penetration Testing
Your web app has vulnerabilities.
Let’s find them first.
What is Web Application Security?
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 security 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.
Who Needs Web Application Penetration Testing?
Web application testing is essential for:
Regular penetration testing validates your security controls, helps meet compliance requirements, and protects your reputation by identifying vulnerabilities before they can be exploited.
OWASP Aligned Testing
Each assessment is tailored to your application’s technology stack, authentication model, and business logic.
Authentication & Authorisation
Multi-factor authentication 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 logic vulnerabilities that automated scanners miss.
Session Management
Session hijacking, cookie security, token handling, timeout configurations, and cross-site request forgery (CSRF) protections.
Data Exposure
Sensitive data in URLs, error messages, source code comments, and insecure data transmission or storage.
API Security
REST and GraphQL API testing, rate limiting, authentication mechanisms, data validation, and API-specific vulnerabilities (OWASP API Top 10).
File Upload & Handling
Unrestricted file uploads, path traversal, arbitrary file access, and server-side vulnerabilities through file processing.
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.
Source Code Review
Manual review of application source code to identify security vulnerabilities, insecure coding patterns, and logic flaws that may not be detectable through black-box testing alone. Particularly valuable for pre-release security validation or high-risk applications.
Infrastructure & Configuration
Security headers, TLS/SSL configuration, subdomain takeover risks, and server misconfigurations that impact application security.
AI & LLMs
Direct or indirect prompt injection, insecure output handling, data poisoning, information disclosure are all potential weaknesses that could be exploited to compromise user or sensitive data.
Common Vulnerabilities We Identify
Broken authentication
Broken authentication and session management are among the most commonly exploitable issues we find. Weak password policies, missing MFA enforcement, and poor session handling can allow attackers to take over user accounts.
Insecure direct object references
Insecure direct object references (IDOR) and broken access control are frequently present in applications where access controls were designed for expected user behaviour, but not tested against an adversarial one. These flaws allow attackers to view or modify other users’ data simply by changing a parameter in a request.
Business logic vulnerabilities
Business logic vulnerabilities are flaws that are unique to your application’s functionality and entirely invisible to scanners. Examples include manipulating a checkout flow to purchase items at a reduced price, bypassing approval workflows, or abusing a free trial mechanism to gain permanent access. These are discovered only through manual, intelligence-driven testing.
Injection vulnerabilities
Injection vulnerabilities, including SQL injection, command injection, and server-side template injection, remain a common vulnerability particularly in older or rapidly developed applications. Successful exploitation can lead to full database access, server compromise, or data exfiltration.
API Security Issues
API security weaknesses are increasingly common as applications rely more heavily on REST and GraphQL APIs. We regularly find missing authentication on sensitive endpoints, insufficient rate limiting, and mass assignment vulnerabilities that expose internal data fields to external callers.
Sensitive Data Exposure
Sensitive data exposure through insecure transmission, verbose error messages, or data leakage in client-side code continues to appear across a wide range of applications, including those that otherwise appear well-secured.
Pricing
for web app penetration testing
No obligation · Strictly confidential · Quote within one business day
Pricing Examples
Indicative ranges only. Your exact price is confirmed after a short scoping conversation – see full service pricing.
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 to proceed, and all enquiries are confidential
Web Application Pentesting – common questions
Most web application tests take 3-7 days depending on scope and complexity. Testing can be performed for your development, staging, or production environments.
Reports are delivered within 2 business days of testing completion.
There is an inherent risk with penetration testing – 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.
Yes, API testing is included when APIs are part of the application’s functionality. The web application penetration test is usually scoped based upon the functionality of the application and not the number of API endpoints that are exposed.
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 (standard user, admin, etc.) 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 you would be required 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 (such as Burp Suite Professional) to enhance our efficiency during the discovery of vulnerabilities within your applications. We do not run a vulnerability scan and call it a day.
Testing is entirely manually-led, intelligence driven, and every finding is validated and exploited by our consultants.
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.
We recommend annual testing at minimum, with additional testing after major releases or breaking changes, significant feature additions, or architectural changes. Many organisations may benefit from continuous testing through our Pentest as a Service offering.
Take a look at our article on what to expect during a web application penetration test. If you’re looking to procure a web app pentest for the first time, we’ve also written an article on how to approach scoping a pentest.
Yes, complimentary focused retesting is included to verify that identified vulnerabilities have been properly remediated. To conduct this type of testing we would require the same level of access to the application and any relevant user roles to repeat the assessment.
As part of our standard operations within Exploitr, we also provide details and repeatable evidence as part of our assessment reports – so your team can validate and verify remediation internally.
Yes, we offer source code review as a complementary service to penetration testing.
Code reviews can identify vulnerabilities in the development phase and provides additional assurance beyond black-box testing. We typically call this “open-book” testing.
Contact us to discuss adding a code review to your engagement.
Yes, we can test the server-side components and APIs that mobile applications interact with. For a more dedicated mobile application assessment, consider pairing with mobile application testing.