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Application security, the whole web layer, continuously.

Every public application, login portal and API endpoint you expose, discovered and assessed from the outside. Security headers, exposed development environments, outdated frameworks and authentication surfaces an attacker would reach first.

CVEs prioritised with CVSS, EPSS and KEV, not ranked by count.

Application Security at a glance

Coverage

What we observe

Public applications and APIs, missing security headers, exposed staging and admin interfaces, outdated framework versions.

Scoring

How it's scored

Each observation maps to a published, versioned rubric. Click any score component to see the evidence behind it.

Action

What happens next

Findings route to the application owner with remediation guidance, and the score moves when the fix is observable.

What we observe

  • Subdomain enumeration and liveness across the estate
  • Technology discovery on live hosts and high-signal paths
  • CVE detection backed by NVD
  • Security headers and their configuration
  • Subresource integrity on third-party assets

What arrives on a finding

  • CVSS, EPSS and KEV status on every CVE
  • Prioritisation by what is actually being exploited
  • The affected asset and how it was discovered
  • Remediation with an SLA
  • MITRE ATT&CK tactic and technique mapping

Anatomy of a finding

FindingKnown-exploited CVE on a public application, on a subdomain not in your asset inventory
EvidenceThe technology and version detected, and the path it was observed on
Why it mattersPresence on the KEV list means exploitation is confirmed in the wild, not theoretical
Who it affectsAnyone who can reach the host, which, being public, is everyone
RemediationPatch or decommission; the asset was likely forgotten rather than accepted

EPSS and KEV prioritised web application vulnerability findings

Application security from outside, without a login

External application assessment covers what a visitor's browser can see, which is less than a code review and considerably more than most organisations check.

Transport security first: TLS version and cipher configuration, certificate validity, chain problems, and expiry. Certificate expiry is worth its own mention because it is the single most common finding across every portfolio, it causes visible outages, and it is entirely preventable, an expired certificate on a payment subdomain is read by an assessor as a maintenance signal well beyond its direct risk.

Then security headers (content security policy, HSTS, frame options, referrer policy) and exposed application components: admin interfaces, API documentation published unintentionally, debug endpoints, version-disclosing responses, and JavaScript dependencies with known vulnerabilities.

What no external assessment can tell you about an application

Authorisation logic, business logic flaws, injection vulnerabilities behind authentication, and anything requiring a valid session are not externally observable. They need authenticated testing, and often source access.

This is the boundary worth being explicit about, because application security is where outside-in tooling is most often oversold. An organisation with a perfect external application score can still have a broken access control on an authenticated endpoint that hands one customer another customer's data, and that is frequently the finding that ends up in a breach notification.

So the module's honest role is hygiene and exposure rather than application assurance. It tells you your transport security is sound and nothing is exposed that should not be. It does not tell you the application is secure, and a vendor claiming their external scan does is describing something that cannot be done.

Hygiene findings correlate with everything else

The findings here are individually modest and collectively predictive. An organisation with expired certificates, missing HSTS, exposed debug endpoints and outdated JavaScript libraries is not usually an organisation with rigorous internal application security practice.

That correlation is why these findings carry weight in vendor assessment out of proportion to their direct severity. You are not primarily worried about the missing referrer policy. You are reading it as a signal about whether anybody is maintaining the estate, and in a context where you cannot see inside, observable maintenance discipline is one of the few honest proxies available.

It is also why remediation is worth doing even when each item looks trivial. The findings are cheap to fix, and fixing them changes what an assessor, an underwriter or a prospective enterprise customer concludes about the organisation behind them.

Where this connects

Network security module →

Services and versions across the external estate.

How scoring works →

How application hygiene findings are weighted.

Vendor onboarding →

Reading hygiene findings as a maintenance signal during evaluation.

Common questions

Rate your own application security first

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