checkout-mobile-cashbacknpm
Advisory published Updated
checkout-mobile-cashback is a confirmed malicious npm package (MAL-2026-12573) that executes malicious code on install (malicious version 35.4.9). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in checkout-mobile-cashback (npm)
What this malware does
[email protected] executes a staged binary dropper on module load. index.js requires./shim, which selects a platform-specific binary URL from a hardcoded list of Cloudflare Workers hosts (oob-worker.cf102-baf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev) assembled via array-join string splitting to evade static matching, with a DNS-TXT chunked base64 fallback channel over sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The fetched bytes are written to /tmp or %TEMP% under disguised names imitating system tooling (.cache<rand>, dotnet_diag_<rand>.exe), chmodded 0755, and spawned detached via /bin/sh -c or cmd.exe /c start /b. No hash or signature verification is performed, the destinations are unrelated to any declared publisher, and the logging function is stubbed to a no-op while a DISABLE_TELEMETRY env-var opt-out provides a telemetry cover story. The behavior fires as a side effect of importing the package.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Search your lockfiles and build artifacts for checkout-mobile-cashback (version 35.4.9).
If you installed it — respond
Remove checkout-mobile-cashback 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 checkout-mobile-cashback 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 checkout-mobile-cashback-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.