Resources · Free to use · No sign-up
Answers you cantake away with you.
Checklists, tools and briefings we publish for anyone defending an organisation, whether or not they ever work with us. Nothing on this page is gated behind a form, and nothing on it tries to frighten you.
Twelve free toolsExternal Exposure ReportCVE ExplorerHeader AnalyserWeekly briefingsChecklists
Guides and checklists
Take one away with you
Basic cyber skills for UK business owners
The nine everyday tasks the government's 2026 research found most UK businesses lack confidence in — firewalls, malware, backups, updates, accounts and more — each in plain English with what to do, mapped to Cyber Essentials, plus a one-page checklist to print.
Questions to ask a SOC provider
Twenty questions in five themes, each with what a good answer looks like, a scoring scheme and the answers that should worry you. Take it into the procurement meeting.
What is here
Use what is useful
External Exposure Report
All eight of the tools below run together against one domain and read as a single report: can your email be forged, what does your DNS give away, how do your website's encryption, headers and cookies hold up, what do the certificate logs remember, can researchers reach you, and what do the threat feeds say about your name. One grade, the fixes in order, and a PDF for the board — free for a name and a work email.
CVE Explorer
Search any vulnerability and see CVSS severity, EPSS exploitation probability and CISA Known Exploited Vulnerabilities status side by side, refreshed daily, with a plain-English verdict on what to do. Companions: a CVE Watchlist for just your products (page, RSS feed and email digest), a rolling “This week in CVEs” digest, the CISA KEV deadline calendar with an .ics feed, and an EPSS trend chart on every CVE.
DNS Audit
Enter a domain and get a plain-English report on weak, insecure and leaking DNS records: private RFC 1918 addresses in public DNS, open zone transfers, SPF, DKIM and DMARC, CAA, DNSSEC, dangling CNAMEs and the host names an attacker would try first.
Email Security Check
Can someone send email as you? Enter a domain and get SPF, DKIM, DMARC, MTA-STS, TLS-RPT, DANE and BIMI read together: the SPF include tree and lookup count, DKIM key sizes, the DMARC policy and reporting, a plain answer on whether the domain is spoofable, and the exact records to publish next.
Security Headers and TLS Checker
Two graded checks of a site's front door: the A+ to F security-headers grade (HSTS, CSP, X-Frame-Options, cookie flags, the headers that leak your stack) with the line that fixes each, and an SSL Labs-style TLS test — certificate chain, protocols, every cipher suite, forward secrecy, OCSP stapling. PDF reports for both.
Certificate Transparency and Cookie & Consent checks
What the public certificate logs say about you — every host name ever issued a certificate, which still resolve, which point at private addresses — and what your site does before anyone clicks accept: cookies, trackers and third-party scripts loaded before consent, with a supply-chain inventory. PDF reports for both.
Reputation Lookup
An IP address from a firewall log or a domain from a link you are not sure about, checked against nine public threat feeds, four mail blocklists, the URLhaus and ThreatFox host lists, the registry's record, reverse DNS, domain age and the shapes lookalike names take. A verdict in plain English; every listing linked to its source. PDF and JSON.
Phishing Header Analyser
Paste an email's headers and find out whether it is really from who it says: SPF, DKIM and DMARC as your mail server saw them, whether From, Reply-To and Return-Path line up, the sending server's reputation, the sender domain's age, and where the links go. Likely legitimate, suspicious, or very likely phishing. Nothing you paste is stored.
security.txt checker and generator
When someone finds a hole in your systems, can they tell you? Check a site's security.txt against RFC 9116 — location, contact, expiry, canonical URL, encryption key, signature — then write a compliant one in a minute with the Apache and nginx lines to serve it.
Threat, sector and threat actor briefings
The public editions of the threat-intelligence reports our SOC writes every week — which groups are active, which techniques are working, what to check in your own estate — sorted by sector with the regulators and schemes that apply, plus profiles of the ransomware and nation-state groups: how they get in and what their victims had in common.
The fortnightly briefing
One email every two weeks: what changed, what to patch, what it means for a UK organisation. Double opt-in, one-click unsubscribe, and an RSS feed if you would rather not give us an address.
Most of what a SOC learns is only useful if it is shared.
Our analysts see the same techniques used against organisations in every sector we monitor. The details of any one client are theirs and stay private; the patterns are not, and keeping them to ourselves would help nobody except the people using them. So the weekly reports are published in a public edition, the CVE data is open, and the checklists are the ones we would want a client to bring to us.
- Cost
- None. No form, no account, no sales call attached.
- Reuse
- Print, share and adapt inside your organisation; a link back is appreciated if you publish.
- Accuracy
- Written by the analysts on shift and reviewed before publication; corrections welcome at hello@cyber-defence.io.
- Feeds
- RSS at /feed.xml; the CVE Explorer has its own sitemap for anything you want to bookmark.
Start a conversation
Something missing?
If there is a question you keep having to answer for your board, your auditor or your insurer, tell us. The next resource on this page is usually the one somebody asked for.