MAL-2026-12763 Malicious code in devplatform-spa-plugin-cobrowsing (npm)

On require() of the package, index.js loads runtime.js which selects a platform-specific endpoint, downloads an opaque binary over HTTPS from obfuscated Cloudflare Workers hosts (hostnames assembled at runtime via array-join, e.g. 'oob-worker.cf<NNN>-<hex>.workers.dev'), with a DNS TXT-record fallback channel under 'c.<domain>' / 'N.<domain>' that returns base64-encoded chunks decoded into the payload. The downloaded bytes are written to /tmp/.cache<rand> (chmod 0755) on Unix or %TEMP%/dotnet_diag_<rand>.exe on Windows, and spawned detached via cp.spawn('/bin/sh',['-c',fp+' &'],{detached:true}).unref() or a cmd equivalent. Destinations are unrelated to the package's stated cobrowsing purpose, hostnames are obfuscated to defeat static analysis, and the payload is executed with no integrity check.

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.