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All fingerprint checksNative function integrity

nonexistent navigator properties return undefined

Check id navigator-proxy-honeypot

What an ordinary browser yields

navigator.rml and the other invented names all read back as undefined, and `'rml' in navigator` is false.

What a detector infers

This reads five navigator property names that exist on no browser — rml, ln, rnd, webdriverPatched and __clearcoteProbe — and additionally evaluates `'rml' in navigator`. The correct answer on every real engine is undefined for all five, and false for the `in` test, so the check has zero false-positive surface by construction: it fails only if something answers a question no browser can answer. A navigator backed by a Proxy with a catch-all get (or has) trap responds to arbitrary keys and thereby reports its own existence, independently of how plausible any real property's value is. The name rml is not arbitrary: it appears in a decompiled commercial detector VM among genuine navigator reads, which is why it is included verbatim.

How to resolve it

Never back navigator with a Proxy that answers arbitrary keys. Spoof individual properties by overriding only the specific accessors you intend to change — ideally at the engine level — so unknown keys fall through to undefined and `in` reports them absent, as on a stock browser.

How anti-bot systems detect automation

Read in the wild by

Kasada

Asks for navigator properties that do not exist, so an over-eager Proxy answers for something real browsers have never had. It also runs an explicit Proxy-invariant probe.

navigator_wireless_devices (no such API), navigator_fake_ln, navigator_fake_rnd, navigator_fake_rml, navigator_fake_v, window_proxy_check

Kasada ips.js teardown — the full 427-probe list

Every attribution traces to a published artifact. See the sources and their limits.

Nearby checks in Native function integrity

See all 13 checks in Native function integrity
Who builds this test

Clearcote is a browser built for fingerprint coherence

It is a Chromium fork, maintained by the same people who wrote this reference. It ships as a compiled browser rather than as a stealth script injected into someone else's — which is a description of how it is built, and is not an argument about how it behaves on this check.

This audit takes no position on how Clearcote scores on Native function integrity checks, on this one, or anywhere else. It has no baseline corpus of other people's fingerprints to rank you against and no vendor scoreboard — nearly every check is self-referential, asking one browser the same question through two independent APIs and reporting whether both answers can be true at once. It runs identically on any browser, including ours. Run it on yours and read the result yourself.

See the other checks in Native function integrity — the family navigator-proxy-honeypot belongs to.