NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
Malicious package

claims-payout-offer-apinpm

Advisory published Updated

claims-payout-offer-api is a confirmed malicious npm package (MAL-2026-12632) that opens a backdoor for remote access (malicious version 35.7.6). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in claims-payout-offer-api (npm)

MAL-2026-12632
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall claims-payout-offer-api

What this malware does

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.

Malicious versions

1 flagged
35.7.6

Indicators of compromise (SHA-256)

249e26d075d4551f9259568bb4029db870432feca831cb4cf7d26ffb7318605b

Detection & response playbook

Backdoor / remote access

  1. Find it

    Search your lockfiles and build artifacts for claims-payout-offer-api (version 35.7.6).

  2. If you installed it — respond

    claims-payout-offer-api establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.

  3. Did it already run?

    If claims-payout-offer-api was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. claims-payout-offer-api on npm has been identified as a malicious package (version 35.7.6 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015138

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks claims-payout-offer-api-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database
claims-payout-offer-api (npm) malicious package — MAL-2026-12632 | O3 Security