CREST-Certified Web Application Penetration Testing for UK Businesses
Manual exploitation of OWASP Top 10 vulnerabilities, business-logic flaws, broken authentication, IDOR, SSRF, and multi-tenant security boundaries. Live findings during testing, free retests after remediation, fixed-price scope within 24 hours.
- Unlimited retesting
- Unlimited pre-retesting
- No hidden fees
“I would highly recommend EJN Labs to any organisation seeking reliable, detailed, and well-managed penetration testing services, particularly for government or enterprise-level projects.”
Imran SaghirProject Lead, SquareOne“There wasn’t another company we could find that could deliver what we needed in the timeframe we needed. The client loved it, and we got instant ROI from the engagement.”
Dan WilcocksonCo-Founder, Celloriof our testing is run by a CREST-certified tester, never a junior or a scanner alone. The breaches that matter hide in business logic, authorisation flows, and chained exploitation, where automated tools cannot reach.
Scanners find patterns. Humans find consequence.
Automated tools catch known signatures: missing patches, default configs, common CVEs. They miss the broken role logic in your admin panel, the IDOR in your KYC flow, and the auth bypass nobody scanned for.
A CREST-certified web application penetration test by a human tester walks the application like a real attacker. Every finding is verified, reproducible, and mapped to OWASP Web Security Testing Guide, ASVS, NIST SP 800-115, and PTES.
ISO 27001, SOC 2, PCI DSS, and FCA SYSC audits accept manual pen test evidence. Scan-only evidence is generally insufficient.
OWASP TOP 10 + BEYOND
What We Actually Test
Manual exploitation across the 10 highest-risk web application vulnerability categories, plus business-logic and multi-tenant scrutiny that scanners cannot find. Each finding is verified, reproducible, and mapped to OWASP, CWE, and CVSS 3.1.
Broken Access Control
IDOR across user records, horizontal and vertical privilege escalation, role-based access bypass, force-browse to admin endpoints, and privilege-reset abuse. The largest single category of real-world breaches.
Cryptographic Failures
TLS configuration scrutiny, weak cipher detection, certificate validation, sensitive data exposure in transit and at rest, weak randomness, and insecure key management.
Injection
SQL injection (boolean / time-based / union / error-based), NoSQL injection, command injection, LDAP injection, XSS (stored / reflected / DOM-based), template injection, and XXE.
Insecure Design
Business-logic flaws scanners cannot find. Voucher abuse, payment manipulation, race conditions, mass-assignment, and workflow-bypass scenarios specific to your application.
Security Misconfiguration
Default credentials, exposed admin interfaces, verbose error messages, missing security headers, directory listing, unnecessary HTTP methods, unrestricted file upload.
Vulnerable Components
Dependency-version analysis against CVE feeds, supply-chain abuse vectors, end-of-life library detection, and exploitability validation against your specific deployment.
Authentication & Session
Authentication bypass, MFA bypass, password reset abuse, session fixation, weak session tokens, JWT manipulation, OAuth flow abuse, credential-stuffing protection validation.
Software & Data Integrity
Unsafe deserialisation, untrusted CDN sources, plugin / package manager abuse, CI/CD security validation, and signed-update verification.
Logging & Monitoring
Log-injection scenarios, sensitive-data leakage in logs, audit-trail gaps for security events, detection-evasion testing for SOC validation.
SSRF
Server-side request forgery against internal services, cloud metadata endpoints (AWS IMDS, Azure IMDS, GCP metadata), filter-bypass techniques, protocol-smuggling.
METHODOLOGY
Web Application Penetration Testing: From Scope to Attestation
CREST-aligned methodology built on OWASP Web Security Testing Guide, OWASP ASVS, NIST SP 800-115, and PTES. Each finding maps to all four standards plus your specific compliance regime.
Reconnaissance
Application mapping, technology fingerprinting, content discovery, parameter enumeration, authentication-flow analysis, role-matrix construction.
Vulnerability Assessment
Authenticated and unauthenticated automated scanning across every user role, plus targeted manual checks for known weakness patterns.
Manual Exploitation
Hands-on testing by a CREST-certified pentester. Business-logic exploitation, chained vulnerabilities, privilege escalation, impact validation.
Reporting + Retest
Executive summary, technical report with CVSS scores and reproduction steps, walkthrough call, free retest after remediation, attestation letter.
CREDENTIALS
Verified Accreditations Auditors Accept
Every credential below is independently verifiable. UK procurement teams, FCA supervisors, ISO 27001 / SOC 2 auditors, and cyber insurance underwriters all recognise these standards.
GET YOUR QUOTE
Get a CREST web app pen test quote in 24 hours
A fixed-price quote back in one business day, from a named CREST assessor. No sales pipeline, no chasing.
- CREST and IASME accredited. Testing your auditors and clients already recognise.
- Fast-track testing within 24 hours where required. Free retest of every fix included.
- Live findings via your client portal, not a four-week PDF.
- Fixed price from £3,500 for a single-role, single-app scope, agreed up front. Most engagements run £5,000 and up. No day-rate surprises.
Dan WilcocksonCo-Founder, CelloriUnder NDA Further named references available on a scoping call.
- We reply within one business day with a fixed-price quote from a named CREST assessor.
- You approve the scope and we book a start date, usually within 24 hours.
- Live findings land in your client portal as we test, with a free retest of every fix.
Get your fixed pen test quote in 24 hours
Quote request received
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COMPLIANCE READY
Reports Mapped to Every Framework
Findings are explicitly tagged to the relevant control reference. Your audit team submits the report directly without translation work.
ISO 27001
Annex A.12.6.1 technical vulnerability management plus A.9 access control validation.
SOC 2 Type I & II
CC6 logical access, CC7 system operations, CC8 change management evidence.
PCI DSS
Requirement 11.3 application penetration testing across cardholder data environments.
FCA SYSC
SYSC 4.1.1R, 6.1.1R, 13 mapped to each finding for FCA-regulated firms.
UK GDPR
Article 32 effectiveness testing, customer-data security controls, ICO-acceptable evidence.
Cyber Essentials Plus
Direct certification through our IASME body status, single-vendor delivery.
PRICING
Transparent Web Application Penetration Testing Pricing
Pricing depends on app complexity, user-role count, business-logic depth, and integration surface. The day count flexes; the included deliverables stay the same across all engagements.
Depends on app complexity
Single user role, basic CRUD application, marketing website with auth. Typically 5-day engagement.
Get a fixed quoteDepends on app complexity
Multi-role SaaS, business application with payment integration. Typically 8-12 day engagement.
Get a fixed quoteDepends on app complexity
Multi-tenant platform, complex authorisation matrix, integration-heavy applications. 15-20 day engagement.
Get a fixed quoteBY SECTOR
Web Application Penetration Testing for Your Sector
Sector-specialist scoping for UK businesses with sector-specific compliance regimes and threat models.
Fintech & FCA-Regulated
FCA SYSC, Open Banking FAPI 1.0, PSD2 SCA, payment-flow scrutiny, KYC/AML testing.
Fintech sector pageSaaS Companies
SOC 2 Type I & II evidence, multi-tenant boundaries, role escalation, customer-tenant isolation.
SaaS sector pageLaw Firms
SRA Cyber Standard, privileged data, conveyancing fraud defence, partner-tier procurement.
Law firm sector pageHealthcare
NHS DTAC, DSP Toolkit v6, UK GDPR Article 32, EHR systems, telehealth platforms.
Healthcare sector pageInsurance
FCA / PRA Operational Resilience, cyber underwriting, claims data, broker portals.
Insurance sector pagePublic Sector
CCS / G-Cloud framework, NCSC-aligned, citizen-facing services, PSN-compliance scrutiny.
Public sector pageWHY EJN LABS
What You Get From Web Application Penetration Testing
Six concrete differentiators competitors don’t all match.
CREST-Certified Testers, Verifiable
Every test by a CREST-certified pen tester (CRT, CCT APP, CCT INF where applicable). Verify our company status at crest-approved.org.
24-Hour Startup, Where Required
From signed scope to active testing in a single business day for incident response, audit deadlines, or regulator-driven timelines.
Live Findings, Not 4-Week PDFs
Critical issues reported during testing through your client portal. Your team remediates while testing continues.
Audit-Ready Reports
Executive summary plus full technical report with CVSS scores and explicit framework mappings (ISO 27001, SOC 2, PCI DSS, FCA SYSC).
Free Retests, Standard
Verify remediation of every finding before close-out. Letter of attestation for audit submission included. Most competitors charge £1,500-£3,000 per retest.
UK-Based CREST Testers
Every engagement performed by vetted, UK-based CREST-certified testers, matched to your needs, security clearance, and compliance scope.
FAQ
Frequently Asked
How long does a web application penetration test take?
Standard engagements run 5-10 working days for active testing, plus 3-5 days reporting and a free retest after remediation. Smaller scopes complete in 5-7 days end-to-end. Complex multi-tenant or integration-heavy applications run 3-4 weeks.
How much does web application penetration testing cost in the UK?
Indicative ranges: small SMB applications £5,000-£8,000, standard SaaS / business apps £8,000-£18,000, enterprise / multi-tenant £18,000-£35,000. Pricing depends on user-role count, business-logic complexity, and integration surface.
What methodology do you follow?
CREST-aligned methodology built on OWASP Web Security Testing Guide (WSTG), OWASP ASVS, NIST SP 800-115, and PTES. Reports map findings to all four standards plus your specific compliance regime.
Do you test in production or a non-production environment?
Most engagements run against UAT or staging. Production testing is supported with explicit firm-side approval, restricted scope, real-time SOC coordination, and incident-response liaison.
What’s the difference between a vulnerability scan and a penetration test?
Vulnerability scans are automated and catch known patterns. Penetration tests are performed by humans and catch business-logic flaws, IDOR, broken authorisation, and chained vulnerabilities. ISO 27001 / SOC 2 / PCI DSS audits accept pen test evidence; scan-only evidence is generally insufficient.
Do you test single-page applications, GraphQL APIs, and modern frontends?
Yes. Our methodology covers React/Vue/Angular SPAs, GraphQL endpoints, WebSocket security, postMessage abuse, CSP bypass, and client-side route-guard bypass.
Can you map findings to our specific compliance framework?
Yes. Reports include explicit mappings to ISO 27001 Annex A.12.6.1, SOC 2 Trust Services Criteria, PCI DSS Requirement 11, FCA SYSC, UK GDPR Article 32, and Cyber Essentials Plus controls.
What’s in the report?
Executive summary (board-ready), technical report with CVSS 3.1 scores, reproduction steps, screenshots, specific remediation guidance, and a 60-minute walkthrough call. Letter of attestation issued after free retest.
Do you sign NDAs?
Yes. We sign client-supplied NDAs as standard. Engagement data is protected under our ISO 27001 (BSI-audited) information security management system.
Can you simulate threat actors targeting our sector?
Yes. For sector-specific engagements we model the actual threat actors active against your industry using TTPs from current threat intelligence.
How quickly can you start?
From signed scope to active testing in 24 hours where required. Standard pipeline is 3-5 business days from initial scoping call to test start.
Are your testers UK-based and what certifications do they hold?
Every engagement is performed by vetted UK-based CREST-certified testers matched to your engagement based on security clearance, compliance scope, and sector specialism. Testers hold CREST certifications relevant to their discipline (CRT, CCT APP, CCT INF, CCSAM).
20+ CREST-certified testing services in one place
Web, mobile, API, cloud, AI, infrastructure, red team. Pick the test that fits your environment.
Get a fixed Web App pen test quote in 24 hours
A CREST-certified pen tester will contact you within one business day with a fixed price, a realistic timeline, and the named consultant. No sales pipeline.
