Go Penetration Testing for Services and APIs
Go services are usually small, fast and hand-rolled, which means the security depends on what each handler remembered to check. We test them handler by handler, role by role. CREST-certified testers, fixed price from £2,780, 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, CelloriThere is no convention layer catching mistakes in a Go service. Authorisation is whatever the middleware chain and the handler do, and middleware that is registered on one router group and not another is the most common finding we write up.
Go will do exactly what you wrote, including the check you forgot
The second area is the outbound side. Go services talk to each other constantly, and a URL that comes from a request, a redirect that is followed by default, or a client that skips certificate verification turns the service into a route into the internal network.
Then concurrency. Goroutines make it easy to check a condition in one place and act on it in another, which is where double spends, duplicate provisioning and quota bypasses live. Those are business logic findings and no scanner will find them.
ISO 27001, SOC 2, PCI DSS and Cyber Essentials Plus audits accept manual penetration test evidence. Scan-only evidence is generally insufficient.
GO SPECIFICS
What We Actually Test in a Go Service
Ten test areas that apply because the service is written in Go, on top of the standard API checks. Every finding is verified, reproducible and mapped to OWASP, CWE and CVSS 3.1.
Handler authorisation
Every route against every role, middleware registration gaps between router groups, and path matching quirks.
Server side request forgery
User controlled URLs in outbound calls, redirect following, and reachability of internal services and cloud metadata.
Path traversal and file serving
File server configuration, path joining, archive extraction and download handlers.
Query construction
SQL built with formatting rather than parameters, and filter or sort values that reach the database.
Concurrency and business logic
Race conditions on shared state, time of check to time of use, and repeated requests that bypass a limit.
Input parsing
JSON decoding behaviour, unknown fields, numeric conversion and size limits.
Tokens and sessions
JWT library configuration, custom middleware, cookie flags and revocation.
gRPC and protobuf
Reflection left enabled, missing authentication interceptors, and message validation.
TLS and transport
Certificate verification, self-signed handling, timeouts and connection reuse.
Build and deployment surface
Profiling and debug endpoints, module dependencies, embedded assets and what the binary discloses.
METHODOLOGY
What a Go finding looks like
Written the way a finding appears in our reports. The example below is reconstructed from publicly documented research, with hosts, paths and identifiers redacted. We do not republish client findings, named or anonymised.
A single HTTP/2 connection exhausts the service
- Affected
- A Go service exposing the public API at [redacted], built with a toolchain three minor versions behind.
- What we found
- The service terminated HTTP/2 directly and processed an unbounded stream of header continuation frames on one connection. One client held the process at full CPU, the health check began to fail, and the instance dropped out of the load balancer pool.
- Why it matters
- Denial of service from a single unauthenticated connection. Nothing in the rate limiting triggered, because as far as the counters were concerned it was one request.
- Fix
- Update the Go toolchain and rebuild, terminate HTTP/2 at a proxy that enforces frame and header limits, and set read header timeouts and maximum header size explicitly rather than relying on defaults.
Reconstructed from public research: CVE-2023-45288, HTTP/2 header continuation handling in the Go standard library and golang.org/x/net.
Go 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 Go application 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 £2,780 for a small, single-scope engagement, agreed up front. Most engagements run £4,190 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
We will reply within one business day with your fixed-price quote from a named CREST assessor.
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or book a 20-min scoping call first
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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 Go 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 days
Single user role, basic CRUD application, marketing website with auth. Typically 5-day engagement.
Get a fixed quote3 to 5 days
Multi-role SaaS, business application with payment integration. Typically 8-12 day engagement.
Get a fixed quote5 to 8 days
Multi-tenant platform, complex authorisation matrix, integration-heavy applications. 15-20 day engagement.
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
Go 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 Go 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
Is this an API test?
Usually yes. Most Go services are APIs, so the engagement is scoped as an API test with the Go-specific checks applied.
Do you test services behind a gateway?
Yes, and we ask for an allowlist so the test measures the service rather than the gateway.
Can you test gRPC?
Yes. We enumerate methods where reflection is enabled and test authorisation per method.
Do you need the source?
No. Source helps with concurrency findings, and a code review is the better tool if that is your main concern.
What about Kubernetes underneath?
That is the container and Kubernetes test. Many clients scope both, because the pod identity is often the next step after a service finding.
Our service is internal only.
Then we test it from the position of a compromised neighbour, which is how it would actually be reached.
What is included in the price?
Scoping, testing, the executive summary, the technical report, a walkthrough call and free retests until the finding is closed. One scope, one number, no follow-up invoices.
How fast can you start?
Scope to active testing in 24 hours once the scope is agreed, subject to tester availability in your window.
Are your testers CREST certified?
Yes. EJN Labs is a CREST member company and testing is delivered by CREST-qualified testers. The membership is verifiable on the CREST marketplace.
20+ CREST-accredited testing services in one place
Web, mobile, API, cloud, AI, infrastructure, red team. Pick the test that fits your environment.
Get your Go service tested properly
Send us the routes and the roles. You will have a fixed scope and a number within 24 hours.
