Windows Build Review
A build review with an attacker sitting at the keyboard: what a standard domain user can reach on the box, which local escalation path still works, and what a stolen laptop gives up offline. CREST-certified testers, fixed price from £1,740, 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, CelloriWe start from a standard user account on a real machine rather than from a policy export. That is the position an attacker reaches after one phishing email, and it is the only position that tells you whether the hardening you paid for is actually applied across the estate.
Baselines describe the build. We test the one your users log into.
Most Windows escalation we find is not a missing patch. It is a writable service binary, a scheduled task running as SYSTEM from a path a user can edit, a local administrator password shared across three hundred machines, or a service account holding SeImpersonatePrivilege on a box that also runs a web application.
Where the build allows it we repeat the checks offline against the disk: cached credentials, DPAPI material, saved wireless keys and unencrypted volumes. That answers the question the board asks first, which is what a stolen laptop gives up before anyone reports it missing.
Every finding comes back mapped to the CIS benchmark item and the Microsoft baseline setting it breaks, so your build engineer closes it in the image rather than one machine at a time.
WINDOWS SPECIFICS
What We Actually Test on a Windows Build
Manual testing from a standard user account against the CIS Microsoft Windows Benchmarks and the Microsoft security baselines, then the escalation paths that actually get used.
Patch and support posture
Servicing channel, missing security updates, unsupported roles and features, and whether the machine is still receiving updates at all.
Local administrators and LAPS
Who holds local administrator rights, whether the built-in account is renamed and disabled, and whether Windows LAPS gives every host a different local password.
Credential exposure
Cached domain credentials, WDigest, LSA protection, Credential Guard state, and what a low privileged user or an offline disk can recover.
Local privilege escalation
Unquoted service paths, writable service binaries and directories, AlwaysInstallElevated, scheduled task permissions, and token privileges held by service accounts.
Application control
AppLocker and WDAC policy, whether it is in audit or enforce, and the signed Microsoft binaries that walk straight around it.
Disk and boot protection
BitLocker configuration, TPM and PIN policy, Secure Boot state, and what an offline attack against the disk actually returns.
Network services and shares
Listening services, SMB signing, NTLM policy, LLMNR and NBT-NS, WinRM and RDP exposure, and share permissions on the host.
Hardening baseline
Measured against the CIS Microsoft Windows Benchmark and the Microsoft security baseline, with the deviations that matter separated from the ones that do not.
Lateral movement
What the credentials, certificates and trusts on this host reach next: other workstations, file servers, hypervisors, and the domain itself.
Logging and detection
Which of the above produced a log, where that log went, and whether anyone would have seen it.
METHODOLOGY
What a Windows build 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.
Local administrator password recovered from the deployment share and valid across the estate
- Affected
- The standard Windows workstation build at [redacted], deployed to [redacted] machines from a share readable by any domain user.
- What we found
- The unattended installation file on the deployment share was readable by every domain user and contained the local administrator password in plain text. That password authenticated on every workstation we tested, and Windows LAPS was not deployed.
- Why it matters
- One compromised account gives local administrator on every workstation, which is the step that turns a single phishing click into a domain wide incident.
- Fix
- Remove credentials from the unattended file and restrict the deployment share, deploy Windows LAPS so every host holds a different local password, disable the built-in administrator account, and block network logon for local accounts.
Reconstructed from public research: the Microsoft guidance on Windows LAPS and local account restrictions, and the CIS Microsoft Windows Benchmark sections on local accounts and credential caching.
Windows Build Review: 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 windows build review 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 £1,740 for a small, single-scope engagement, agreed up front. Most engagements run £2,760 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.
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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 Windows Build Review Pricing
Pricing depends on the number of builds and roles in scope, how much the estate varies from host to host, and the depth of the configuration review. The day count flexes; the included deliverables stay the same across all engagements.
1 to 2 days
Single user role, basic CRUD application, marketing website with auth. Typically 5-day engagement.
Get a fixed quote2 to 4 days
Multi-role SaaS, business application with payment integration. Typically 8-12 day engagement.
Get a fixed quote4 to 7 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
Windows Build Review 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 a Windows Build Review
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 Windows build review take?
One to two days for a single standard image, two to four days for a server and workstation pair, four to seven days for a mixed estate with several roles. Reporting is included in the quoted days.
How much does a Windows build review cost in the UK?
From £1,740 for a single build. Most reviews land between £2,760 and £4,580. The quote is fixed before we start and does not move because we found more than expected.
What methodology do you follow?
The CIS Microsoft Windows Benchmarks and the Microsoft security baselines for the configuration review, NIST SP 800-115 and PTES for the attack path work. We test the deviations rather than reprinting the full benchmark output.
Do you need domain admin to run the review?
No. We ask for a standard user account, because that is what an attacker gets. A local administrator account speeds up the configuration read, but it is optional and we will tell you what it changes.
Do you test the gold image or a live machine?
Both, if you want. The gold image tells you what you build; a machine that has been in the field for a year tells you what you actually run. The gap between the two is usually the finding.
Is this the same as a Cyber Essentials assessment?
No. Cyber Essentials asks whether a control exists. A build review asks whether the control holds when someone attacks it, and shows you the path when it does not. The output supports a Cyber Essentials Plus submission.
Can you review Windows Server and Windows 11 in the same engagement?
Yes, and it is the common case. Server and workstation builds share an Active Directory and share most of their escalation paths, so they are cheaper and more useful reviewed together.
What is in the report?
An executive summary, every finding with evidence and reproduction steps, the CIS or Microsoft baseline item it breaks, a fix that names the GPO or registry setting, and a letter of attestation you can send to a customer.
Do you retest after we fix the findings?
Yes, unlimited and with no time limit. Retesting is included on every tier, and the report is reissued once the findings are closed.
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Get your Windows builds reviewed
Send us the image or a machine from the fleet. Fixed quote within 24 hours, CREST-certified testers, unlimited retesting until every finding is closed.
