Description

On require()/import of the package, both adapter.js and the advertised main module lib/telemetry.js download an OS-specific binary from obfuscated third-party endpoints (Cloudflare Workers subdomains oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf102-baf.workers.dev, with a DNS-TXT chunked fallback via sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru), write it to /var/tmp/.cache or %TEMP%\dotnet_diag_.exe, mark it executable via fs['chmod'+'Sync'](path, 0o755), and spawn it detached via cp.spawn('/bin/sh', ['-c', filePath + ' &'], {detached:true, stdio:'ignore'}) or cmd equivalent. Hostnames, filesystem API names, and the child_process require string are reassembled at runtime through string concatenation and.join('') to evade static detection. The dropper is duplicated across _adapter.js and lib/telemetry.js so execution occurs even if one path fails. The fetched payload is opaque, unpinned, unverified, and unrelated to the package's stated purpose (Common TypeScript definitions).

Mitigation

Aliases