OpenSSF/OSV advisory MAL-2026-11508 confirms this npm version as malicious. beaver-ui-header@12.3.9 advertises itself as a UI header library but ships a setup.js that runs on npm postinstall and again on require via index.js. It reconstructs network destinations at runtime by joining arrays of substrings (e.g. ['oob-wor','ker.cf','99-9b3.wor','kers','.dev']) to hide Cloudflare Workers hosts of the form oob-worker.cfNN-*.workers.dev, with a DNS-TXT fallback channel that reassembles a base64...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in beaver-ui-header (npm)
Details
beaver-ui-header@12.3.9 advertises itself as a UI header library but ships a setup.js that runs on npm postinstall and again on require via index.js. It reconstructs network destinations at runtime by joining arrays of substrings (e.g. ['oob-wor','ker.cf','99-9b3.wor','kers','.dev']) to hide Cloudflare Workers hosts of the form oob-worker.cfNN-*.workers.dev, with a DNS-TXT fallback channel that reassembles a base64 payload from numbered TXT records under *.dl.well1.site (c.<domain>, 0.<domain>, 1.<domain>,...). A platform-specific binary is downloaded, staged under /var/tmp or the Windows TEMP directory with a disguised name (dotnet_diag_<tag>.exe on Windows,.cache_<tag> on Unix), chmodded 0755, and launched detached/unref'd via execFile with stdio ignored. Setup.js also invokes execSync('powershell...') on Windows. Variable and env-var names (analytics_state, DISABLE_TELEMETRY, ANALYTICS_OPT_OUT) and the dotnet_diag_ filename frame the flow as telemetry, but the package's stated purpose (UI header component) has no need for platform-specific native binaries, and the destinations are not the publisher's infrastructure. There is no version pin, hash, or signature verification on the downloaded binary.
## Source: ghsa-malware (16b97a60edb5f178da1f1d6f0a672954c9593941bacb970c4ebee657fb766bfe) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
Decision reason
OpenSSF Malicious Packages via OSV confirms beaver-ui-header@12.3.9 as malicious (MAL-2026-11508): Malicious code in beaver-ui-header (npm)