claims-claims-api-adaptersnpm
Advisory published Updated
claims-claims-api-adapters is a confirmed malicious npm package (MAL-2026-12610) that steals credentials and exfiltrates sensitive data (malicious version 35.7.9). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in claims-claims-api-adapters (npm)
What this malware does
On require, index.js loads loader.js which selects a platform-specific temp path, downloads a binary over HTTPS from anonymous *.workers.dev hosts whose names are reconstructed at runtime by joining split string fragments (e.g. oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf102-baf.workers.dev), writes the bytes to a stealth filename (dotnet_diag<rand>.exe on Windows,.cache_<rand> on Linux/macOS), chmods 0755, and spawns it detached via /bin/sh -c or cmd. If HTTPS retrieval fails, the loader falls back to a covert DNS-TXT channel against sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru, requesting c.<domain> for a chunk count and <i>.<domain> for up to 2000 base64 chunks, concatenating and base64-decoding the result into the payload buffer that is then written and executed. No hash or signature verification is performed; destination hostnames are obfuscated to evade static inspection.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for claims-claims-api-adapters (version 35.7.9).
If you installed it — respond
claims-claims-api-adapters is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If claims-claims-api-adapters 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
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks claims-claims-api-adapters-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.