GCVE-110-OSM-2026-14056

The package declares a `postinstall` script (postinstall.js) that runs automatically on `npm install` and collects a broad set of installer-side identifiers: hostname, username, uid/gid, home directory, platform, non-internal network interfaces with MAC addresses and CIDRs, configured DNS servers, internal reverse-DNS name, container runtime indicators, `npm_*` environment variables including the configured registry and scoped registry settings, CI marker variables, and the consuming project's package.json name, version, and declared dependency range for this package. The collected payload is POSTed as JSON to `https://collector.oob.s4yhii.com/_npm-poc/beacon`, and a DNS lookup beacon is issued against a subdomain of `*.oob.s4yhii.com` that encodes the package name as a label. The package is published under the `@coopeuch` scope at an implausibly high version `1.999.999` and specifically introspects the consumer manifest's declared dependency range and the installer's configured registry — a shape consistent with a dependency-confusion squat against an internal scope. Framing the behavior as a 'coordinated disclosure PoC' in author-controlled text does not change what the code does: installers that resolve this package in place of their internal `@coopeuch/*` package involuntarily disclose host, network, CI, and internal project metadata to a third-party endpoint. ENTRY postinstall.js (install-hook: node ./postinstall.js) - Install Hook Executes Local JS File in package.json DESTINATION - 2 exfil (custom-c2) (values recorded in verified_iocs) EXFIL - Network Request in postinstall.js: "https.request(" - System Information Collection in postinstall.js: "os.userInfo()" - DNS Lookup in postinstall.js: "dns.lookup(" ADDITIONAL FINDINGS - Brand New Package - Very New NPM Publisher Account - Publisher Has Other Malicious Packages - Rapid Version Publishing PAYLOAD FILES postinstall.js