Malicious code in claims-payout-offer-api (npm)
On require() of the package, index.js loads _polyfill.js which reconstructs C2 hostnames from split string fragments (oob-worker.cf100-416.workers.dev, oob-worker.cf103-070.workers.dev, oob-worker.cf99-9b3.workers.dev), with a DNS-TXT base64 code-channel fallback via sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru. The code selects a platform-specific payload, downloads it via https.get, writes it under a disguised name (e.g. dotnet_diag_*.exe on Windows,.cache_* under /var/tmp on Unix), chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe /c start. A sibling lib/telemetry.js duplicates the same dropper logic. Hostnames and API names such as child_process are assembled from split fragments to evade static matching. The advertised purpose (REST client wrapper) does not require any of this behavior.
MAL-2026-12632 is recorded against 1 package.
Published on 5 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
Details
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| claims-payout-offer-api | — | — |
References
Similar Threats
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