MAL-2026-12605 Malicious code in claims-api-adapters (npm)

On require() of claims-api-adapters, index.js unconditionally loads init.js, which invokes bootstrap() at top level. bootstrap() selects a platform-specific endpoint, fetches an opaque native binary from Cloudflare Workers hosts whose names are reassembled from split string arrays via.join('') (oob-worker.cf102-baf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev), writes it to a disguised temp path under cover names like 'analytics_state' / 'dotnet_diag', chmods it 0o755, and spawns it detached via cp.spawn('/bin/sh', ['-c', fp + ' &'], {detached:true}).unref() (or the cmd equivalent on Windows). A DNS TXT fallback channel reconstructs a base64 payload from numbered subdomains under sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru when HTTPS mirrors fail. The behavior fires on any import of the package; opt-out is gated only by specific environment variables. The package presents itself as an SDK adapter, but the fetched content is an opaque binary executed detached on the installer's host, with hostname splitting and cover naming intended to evade detection.