claims-payout-offer-domainnpm
Advisory published Updated
claims-payout-offer-domain is a confirmed malicious npm package (MAL-2026-12634) that executes malicious code on install (malicious version 35.6.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in claims-payout-offer-domain (npm)
What this malware does
On require() of the package, index.js unconditionally loads vendor.js, which selects an OS/arch-specific payload path and fetches an opaque binary over HTTPS from string-obfuscated Cloudflare Workers hosts (oob-worker.cf*-*.workers.dev, assembled at runtime via array-join to evade static analysis). A DNS-TXT covert-channel fallback reads a chunk count from c.dl.wel1.ru and reassembles base64-encoded bytes across numbered subdomains of dl.wel1.ru. The fetched bytes are written to /tmp or %TEMP% under disguised names (e.g. dotnet_diag.exe,.cache_), chmod 0755, and spawned detached via /bin/sh -c or cmd. No pinning, hash check, or signature verification is performed, and the destinations are not the publisher's infrastructure.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for claims-payout-offer-domain (version 35.6.1).
If you installed it — respond
Remove claims-payout-offer-domain from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If claims-payout-offer-domain 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-payout-offer-domain-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.