Secure Source Code Review
Manual secure source code review by OSCP/OSWE engineers across Europe. We read the code an attacker would abuse, map to OWASP, and give you a fixed quote.
A secure source code review reads your application the way an attacker reads it, at the level where the bug actually lives: the line that trusts user input, the query built by string concatenation, the token check that never runs. We do this manually, by engineers who exploit code for a living, so the findings are real and the fixes are precise.
Scanners are good at volume and bad at judgment. They flag a thousand “issues” and miss the one authorization check that lets a normal user read another tenant’s invoices. A review by a person who has written and broken this kind of code catches the logic an automated pass cannot reason about, and it does so before the flaw ships to production where it costs far more to fix.
What a source code review actually covers
We look at the parts of the codebase where security decisions are made and often quietly wrong: how input crosses a trust boundary, where authorization is enforced (or assumed), how secrets are stored, and how data flows from a request to a database, a shell, a template or a downstream service. The point is not a coverage percentage. The point is finding the handful of flaws that would actually end up in an incident report.
How we run a source code review
Our approach pairs targeted tooling with hours of reading by a human who understands the framework. Tools narrow the search; the engineer decides what is exploitable. This is where a source code review is the best method for preventing injection attacks that a black-box test might never reach, because we can see the exact sink and the exact missing sanitizer, not just a symptom in a response.
Scoping and threat modeling
Before reading a line, we agree on what matters: which services hold sensitive data, which endpoints face the internet, what a breach would actually cost you. We build a light threat model so the review time goes to the code that carries risk, not evenly across every utility file. You tell us the crown jewels and we start there.
Automated pass and triage
We run the analysis engines suited to your stack and treat their output as a to-do list, not a report. Every candidate finding is opened in the code and either confirmed with a data-flow trace or discarded. You never receive a raw scanner dump with our logo on it.
Tooling we use
Among the best source code review tools we reach for are Semgrep and CodeQL for custom taint queries, plus language-specific engines: Bandit for Python, Brakeman for Ruby on Rails, gosec for Go, ESLint security rules and npm/yarn audit for Node, and Snyk or OWASP Dependency-Check for the dependency tree. For larger commercial estates we work with Checkmarx and Fortify output where you already own it. Choosing the best open source code review tools depends on the language and the framework, and we tune the rules to your code rather than running defaults.
Manual review of high-risk paths
This is the core of the engagement. We follow untrusted data from the entry point to every sink, read the authorization layer endpoint by endpoint, and check the assumptions the framework quietly makes on your behalf. Most serious findings we report come from this stage, not the scanner.
Reporting and a fix session
You get a written report and, if you want it, a call with the engineer who did the work so your developers can ask “why” and “how do we fix this properly” rather than guessing from a ticket.
Vulnerability classes we find in code
Every codebase has its own accidents, but the categories repeat. Reading against OWASP Top 10 and the CWE Top 25 gives us a checklist; experience tells us where each one tends to hide in your framework.
Injection
SQL injection built by string concatenation, command injection through a shell call that interpolates a filename, and template injection in server-rendered views. We trace the exact variable and show the line where parameterization or encoding is missing, which is why a source code review owasp top 10 assessment closes injection risk more reliably than fuzzing from outside.
Broken access control
The most common serious finding we report. An endpoint that fetches a record by ID and never checks who owns it. A role check on the UI but not the API. A multi-tenant query that trusts a tenant ID from the request body. These rarely show up in a scanner and they are exactly what pays a bounty hunter.
Insecure deserialization and unsafe reflection
Objects rebuilt from user-supplied data, dynamic class loading driven by a request parameter, and gadget chains in the dependency set. In several .NET and Java reviews the entry point to full remote code execution was a single deserialization call nobody thought was reachable.
Secrets and configuration
Live API keys in a committed .env, a signing secret hardcoded in a constant, debug flags left on, and permissive CORS built for a demo and never tightened. We check the git history too, because a secret deleted in the latest commit is still sitting in the log.
Weak cryptography and session handling
MD5 or SHA-1 for passwords, static IVs, predictable tokens from a non-cryptographic random source, and JWTs that accept the “none” algorithm. We verify how sessions are issued, rotated and invalidated, not just that a library is imported.
Want this tested on your own systems?
Free 20-minute scoping call, a fixed price with no hourly surprises, and a free retest once you fix what we find.
Languages and stacks we review
We work across the stacks European product teams actually ship: Java (Spring), C# and .NET, Python (Django, Flask, FastAPI), PHP (Laravel, Symfony and legacy code), JavaScript and TypeScript on Node, Go, Ruby on Rails, and mobile in Kotlin and Swift. If your codebase mixes several of these behind an API gateway, that seam is often where authorization gets dropped, and we test it deliberately.
Framework-aware, not framework-blind
A finding in Spring Security looks nothing like the same class of bug in Express middleware. Reviewing with knowledge of the framework’s defaults means we catch the checks you assumed were automatic and the ones that silently do nothing when configured wrong.
Why manual review beats a scanner alone
A static analyzer cannot tell you that a refund endpoint lets a customer refund an order twice, or that “admin” is derived from a header the client controls. It has no model of your business rules. Following source code review best practices means using tools to cover the mechanical patterns and spending human hours on the logic that decides who can do what to whose data. That balance is what separates a useful review from a noisy one.
What you get
Deliverables are written to be actioned by developers and understood by whoever signs off the risk.
- An executive summary that states the real business risk in plain language, without jargon padding.
- A technical report with each finding scored by CVSS, the exact file and line, a data-flow explanation of why it is exploitable, and a concrete code-level fix.
- Findings prioritized so your team fixes the two things that matter this week before the twenty that can wait.
- A remediation call with the reviewing engineer, and a free retest of the fixes once you have made them.
- Where you need it, an attestation letter mapping the work to your compliance obligation.
Compliance and standards
A documented review supports several frameworks directly. PCI DSS 4.0 calls for review of custom code before release (requirement 6.2.4) and for addressing common coding vulnerabilities (6.2.4 and 6.3). ISO 27001:2022 control A.8.28 covers secure coding, and A.8.8 covers technical vulnerability management. SOC 2 change-management criteria expect evidence that code is checked before deployment. For GDPR and DORA, showing that you review the code handling personal or financial data is part of demonstrating due care. We align the report and attestation to whichever of these you are answering to.
Pricing
The source code review cost depends on how much code is in scope, how many languages and services it spans, and whether we review a single critical component or a whole product. Here is the shape of a typical European engagement.
| Engagement | What’s included | Timeline | Price |
|---|---|---|---|
| Focused component | One critical service or module (up to ~15k lines), single language, high-risk paths and dependency check, full report and free retest | 3–5 working days | from €2,500 |
| Application review | A full application with an API and several roles, threat model, taint analysis end to end, exec + technical report, remediation call | 5–9 working days | €3,500–€8,000 |
| Advanced / high-risk | Complex or regulated codebase, multiple services, payment or auth flows, git-history secret sweep, attack-chaining across components | 9–15 working days | €8,000–€20,000 |
| Compliance add-on | Mapping and attestation letter for PCI DSS, ISO 27001, SOC 2, GDPR or DORA | with any tier | from €800 |
| Custom / large estate | Multiple repositories or a monorepo across teams, scoped to your needs | on scoping | custom |
Every engagement is fixed-price, quoted after a free 20-minute scoping call — no hourly surprises, and a retest is included. Get a fixed quote
FAQ
How much does a source code review cost?
What makes you a good source code review provider rather than just running a scanner?
Is a source code review the best method for preventing injection attacks?
Do you need access to our repository?
Which languages and frameworks do you cover?
What tools do you use?
Will this satisfy PCI DSS or ISO 27001?
Is a retest included after we fix?
Related services
Product and engineering teams shipping software that handles money, personal data or authentication, teams preparing for a PCI DSS, ISO 27001 or SOC 2 audit, and any company inheriting a codebase they did not write and need to trust. We are a European team working with clients EU-wide and remotely.
Security you can prove
The same standard on every engagement, big or small.
Evidence, not opinions
Every finding ships with a reproduction and proof of concept — no vague "maybe vulnerable".
Humans over scanners
Certified engineers find the logic flaws and chained attacks automated tools walk straight past.
Fixed price, free retest
You know the cost up front, and verifying the fix is part of the deal — not a second invoice.
Ready to lock this down?
Free scoping call, fixed price, free retest. Tell us what you're running and we'll take it from there — usually within one business day.
Tell us what you're running
Scoping is free. We reply within one business day, and under 30 minutes for active incidents.