Implicit permissions
The backend trusts the request.
A simple ID change is enough.
Security audit for fast-moving SaaS teams
Your API is already leaking. You just don’t know what yet.
Someone may already be able to read data that does not belong to them. Without breaking anything.
Check before someone else does.
Audits run on SaaS, fintech and marketplace APIs.
Max 3 audits / week
Next slot: May 12
ReactNext.jsNode.jsNestJSExpressGraphQLFlutter / Dart
The problem
A breach rarely starts with a hack.
In most cases, nothing is “broken”. The API responds. Routes work.
That is exactly the problem.
Attackers do not exploit bugs. They exploit what you allowed through.
And in most cases, it’s already there. In production.
Probably yours.
Here’s what it looks like in practice:
Over-sharing responses
The API returns more than needed: roles, emails, internal flags.
That data becomes exploitable.
Bypassable business logic
A missing condition. A client-side check.
The logic can be bypassed.
The method
72h to find what can be exploited.
The application is tested like an attacker would. Not to verify it “works”. To see how it can be used against you, concretely.
What an attacker can do immediately
One token is enough to access another account
Internal routes are reachable without authorization
Other users’ data is accessible
What makes this possible
Server-side validation can be bypassed
An executable file can be uploaded
The API reveals internal information through errors
Unintended actions can be chained
Already found in production. Probably yours too.
What we find in production
The same access points already exist in production.
Even when everything “works”.
Here’s what’s already in production:
Impact
Nothing triggers. But the access is already there.
Every finding maps to a real access on your API.
No assumption. No false positive.
These vulnerabilities already exist in most APIs. In production, today.
Cross-account data access
Invoices, profiles or documents from other customers readable.
Sensitive endpoint exposed
Internal routes reachable without access control — access to data or actions outside your API’s intended scope.
Reusable or forgeable JWT
Account access via reusable or forged token.
Admin route reachable
Admin access reachable from a standard account.
Deleted data still readable
Deleted data still accessible through the API.
Server validation bypass
Backend accepts invalid or manipulated data.
Exploitable upload flow
Files accepted without sufficient control. Execution or storage abuse possible.
Verbose backend error
Internal paths, IDs or backend logic exposed.
The most common ones. Not the most severe.
Audit report extract
Without proof, vulnerabilities stay in production. They get exploited.
Every flaw is reproduced with exploitable proof, directly on your API.
No interpretation. No doubt.
You know what to fix.
Concrete proof. Not guesswork.
An actionable report. Not a PDF nobody opens.
CRITICAL
Unauthorized access to another user’s data
Impact
Unauthorized access to customer data. Legal risk and loss of trust.
Exploit
Changing an ID in an authenticated request.
Proof
Reproduced request → access to another account’s data confirmed.
Fix
Strict server-side check + authorization test.
Priority
Immediate fix required
Real finding from an audit
One ID changed. Another customer’s data exposed.
A logged-in user. One modified request. Access to another customer’s data.
No error. Valid response. Data exposed.
Request sent
GET /api/invoices/INV-2846 HTTP/1.1Authorization: Bearer eyJhbGci...// INV-2846 belongs to another account
Response received
HTTP/1.1 200 OK{ "id": "INV-2846", "customer": "alice@other-account.com", "amount": 4800, "status": "paid", "items": [...]}
Finding
Endpoint
/api/invoices/:id
Type
Accès non autorisé aux données
Impact
Any authenticated user can access another customer’s data.
Fix
Strict server-side access check.
This is the type of flaw we identify in 72h.
This is not hypothetical. It is already exploitable.
In 72h, you see what can be used against you.
That is enough. And it ships to production.
€1500 Delivered in 72h
What you get in 72h:
- Access to other users’ data
- Endpoints exploitable without tricks
- Exploitable proof you can reproduce
- Concrete fixes ready to apply
Max 3 audits / week
Limited slots
Payment → access form → audit launched within 2 business hours.
FAQ
Before you open your API to us.
We already have developers. What is the point?
FréquentYour developers build. We test what your API lets through.
What works is not necessarily secure. In fact, it’s often the opposite.
Our application is small. Is this useful?
FréquentYes. Vulnerabilities exist as soon as the first endpoint is exposed.
A few exposed accounts is enough to create a customer, legal or commercial issue.
Do you only work in TypeScript?
The code audit is specialized in TypeScript / Node / React.
API analysis (exposure, permissions, data) applies to any stack.
Do you fix the vulnerabilities?
You receive a clear plan: impact, proof, fix.
Fixes can then be handled.
But you already know what to fix.
Why now?
Because these vulnerabilities already exist.
The only question: when they will be exploited.
How much time does it take on your end?
Very little. Repo access + an API URL is enough to get started.
No long team mobilization required.
Vulnerabilities don’t warn you.
They ship to production.
You have your answer.
The only question: what is your API letting through right now?
Someone already has access to your data.See what they see. Before they do.
Audit in 72h
Audit started immediately.
Actionable results in 72h.
Without blocking your team.