fbc-guard@0.1.0
CAUTION· install onlyPublisher claims: "Lets an AI assistant statically scan HTML and JavaScript landing-page code that turns Meta's fbclid URL parameter into the _fbc cookie (and hand-written _fbp cookies), flagging known ways the click ID is changed, truncated, or kept from an older ad, without executing the code or contacting Meta." Observed in sandbox: no network, touches nothing outside the project, writes no memory.
Coverage
Nothing executable in the bundle ran; the trace covers the install step only.- Tested
- every file read, file written and host contacted by what ran
- Not tested
- use of the skill by an agent
What this means for the label: Caution here covers what ran. The server's tools were not exercised with a real credential, so nothing about their behavior is asserted; the credential summary below says what to do with that.
Before you give it your token
- It will ask for
- no credential variables read in the code
- Where it talks to
- no vendor host named in the codeAlso nothing-here.invalid, facebook.com, googletagmanager.com, facebook.net — not the publisher's domain; check what for before connecting.
- What the honeypot saw
- no credential files read · no network
- What we could not test
- use of the skill by an agent
Connect it under the guard. Nothing executable in the bundle ran; the trace covers the install step only. The code names no credential variable; the guard pins the network to what the honeypot saw and logs every call.
Never paste a credential into a chat, a ticket or a report, including ours. How the guard holds it.
Is [email protected] safe to install?
KillerSkills ran it in the KillerSkills honeypot sandbox (1 scenario; nothing executable in the bundle ran; the trace covers the install step only) on 2026-11-15 and scored it 73/100 (Caution). It is not known to be malicious, but it has behaviour or code a security policy should decide on before install. Notable findings: document.cookie access; document.cookie access; document.cookie access. Summary: no network, touches nothing outside the project, writes no memory.
Behavior trace
Honeypot run · 0 s · 1 scenarios · 0 deviationsStatic findings
var ck=document.cookie;Fix: Replace encoded or assembled strings with plain literals and remove undeclared network calls.var ck=document.cookie;Fix: Replace encoded or assembled strings with plain literals and remove undeclared network calls.var current = (document.cookie.match(/(?:^|;\s*)_fbc=([^;]*)/) || [])[1] || '';Fix: Replace encoded or assembled strings with plain literals and remove undeclared network calls.document.cookie='_fbc=fb.'+sdi+'.'+Date.now()+'.'+fbclid+';path=/;domain=.'+root;Fix: Replace encoded or assembled strings with plain literals and remove undeclared network calls.for (const u of [`http://localhost:${site.address().port}/lp/`, `http://[::1]:${site.address().port}/`, "http://169.254.169.254/latest/meta-data/", "http://10.0.0.1/", "http://2130706433/"]) {Fix: Stop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.for (const u of [`http://localhost:${site.address().port}/lp/`, `http://[::1]:${site.address().port}/`, "http://169.254.169.254/latest/meta-data/", "http://10.0.0.1/", "http://2130706433/"]) {Fix: Replace encoded or assembled strings with plain literals and remove undeclared network calls.document.cookie='_fbc=fb.1.'+Date.now()+'.'+decodeURIComponent(fbclid)+';path=/';Fix: Replace encoded or assembled strings with plain literals and remove undeclared network calls.res.end("document.cookie='_fbc=fb.1.'+Date.now()/1000;");Fix: Replace encoded or assembled strings with plain literals and remove undeclared network calls.env: { ...getDefaultEnvironment(), ...env },Fix: Stop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.Cost to the agent
Tokens estimated at four characters each. Skills load their instruction text when triggered; the figure is what that costs.
Known vulnerabilities
Vulnerability advisories (OSV) cover npm and PyPI packages; this registry has no advisory database.
What would make this Verified
7 points to 80 · weights: behavior 45%, static 25%, prompt 15%, publisher 15%- URL to the cloud instance metadata address≈ +9 on the totalStop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
- Unclaimed publisher≈ +8 on the totalClaim adsandcode: a verified publisher gets +50 on publisher trust. It is free and usually instant with GitHub sign-in.
- document.cookie access≈ +4 on the totalReplace encoded or assembled strings with plain literals and remove undeclared network calls.
- Access to sensitive file paths≈ +4 on the totalStop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
- URL to a private-network address≈ +1 on the totalReplace encoded or assembled strings with plain literals and remove undeclared network calls.