Auth0 Penetration Testing for Customer Identity
Auth0 gives developers a place to put custom logic in the login flow, and that is exactly where things go wrong. An Action that adds a role from an unvalidated claim will hand out privilege quietly and permanently. CREST-certified testers, fixed price from £3,180, scoped in 24 hours.
- Unlimited retesting
- No rescheduling or cancellation fees
- Fixed quote within 24 hours
“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, CelloriAuth0 handles the protocol work correctly. What it also does is let you run your own JavaScript inside the authentication pipeline through Actions, and historically Rules. That code decides what ends up in the token, and it is written by application developers rather than identity specialists.
Why Auth0 risk sits in your custom logic
The pattern we find most often is an Action that reads something the user controls, an email domain, a signup metadata field, a social profile attribute, and turns it into a role or permission claim without validating it. Anyone who can influence that input can grant themselves access.
After that it is application configuration: callback URLs with wildcards, refresh token rotation left off, the implicit grant still enabled for a modern SPA, and a Management API token sitting somewhere it should not be.
ISO 27001, SOC 2, PCI DSS and Cyber Essentials Plus audits accept manual penetration test evidence. Scan-only evidence is generally insufficient.
ACTIONS, TOKENS + TENANTS
What we actually pen test on an Auth0 tenant
Manual pen testing across tenant and application settings, custom Actions and Rules, token issuance and validation, connections and the Management API.
Actions and Rules logic
Every Action and Rule read and tested for claims derived from user-controlled input, role assignment without validation, secrets in code, and whether failure paths let a login through that should have been stopped.
Token issuance and validation
Access and ID token contents, audience and issuer validation at the API end, expiry and refresh token rotation, whether tokens carry more scope than the client needs, and replay of a token past logout.
Application and callback configuration
Callback and logout URL wildcards, allowed origins, grant types enabled per application, whether the implicit flow is still permitted, and PKCE enforcement on public clients.
Connections and identity sources
Database connection settings, password policy and breached password detection, social and enterprise connections, and whether account linking can be abused to take over an existing account.
Management API exposure
Machine-to-machine applications, their granted Management API scopes, whether any can create users or alter roles, and where those credentials are stored.
Tenant and multi-tenancy boundaries
Organisation and tenant separation where you use it, whether a user in one organisation can reach another’s data through the token, and administrative access to the Auth0 dashboard itself.
METHODOLOGY
Auth0 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 Auth0 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
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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 27001:2022
Annex A.8.8 management of technical vulnerabilities plus A.5.15-5.18 and A.8.2-8.5 access control validation.
SOC 2 Type I & II
CC6 logical access, CC7 system operations, CC8 change management evidence.
PCI DSS
Requirement 11.4 application penetration testing across cardholder data environments, including ecommerce penetration testing for online retail platforms.
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 Auth0 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.
2 to 3 testing days
Single user role, basic CRUD application, marketing website with auth. Around 5 working days from kickoff to report.
Get a fixed quote3 to 5 testing days
Multi-role SaaS, business application with payment integration. Around 8 to 12 working days from kickoff to report.
Get a fixed quote5 to 7 testing days
Multi-tenant platform, complex authorisation matrix, integration-heavy applications. Around 15 to 20 working days from kickoff to report.
Get a fixed quotePart of Technologies We Pen Test. These are examples of the stacks we publish pages for, not a complete list. If yours is not here we still test it. Related pages:
BY SECTOR
Auth0 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 Auth0 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
Do you need access to our Auth0 tenant?
Read access to the tenant configuration makes this far more valuable, because most findings are in Actions and application settings. We can work black box from the login flow alone, but it finds a fraction of what a configured review does.
Do you test our API as well?
The token validation at your API is in scope, because a perfect Auth0 configuration means nothing if the API does not check the audience. Full testing of the API’s own logic is a separate engagement we often run alongside.
We still have Rules rather than Actions. Is that a problem?
Not for testing. Rules are deprecated so we will flag the migration, but we read and test them the same way. Legacy Rules tend to carry the oldest and least reviewed logic, so they are usually worth the attention.
Is this relevant if we use Auth0 purely for social login?
Yes, and account linking becomes the main question. If a user can sign in with a social provider that shares an email address with an existing database account, the linking behaviour decides whether that is convenience or account takeover.
What do we get at the end?
A report mapped to ISO 27001 and SOC 2, a developer write-up with reproduction steps, a walkthrough call and unlimited free retesting until every finding closes.
20+ CREST-accredited testing services in one place
Web, mobile, API, cloud, AI, infrastructure, red team. Pick the test that fits your environment.
Get a fixed price for your Auth0 tenant
Tell us how many applications and Actions are in play and whether your API is in scope. You get a fixed-price quote from a named CREST assessor within one business day and unlimited retesting.
