checkout-pay-widget-logicnpm
checkout-pay-widget-logic is a confirmed malicious npm package (MAL-2026-12585) that opens a backdoor for remote access (malicious version 35.3.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in checkout-pay-widget-logic (npm)
What this malware does
On require('checkout-pay-widget-logic'), index.js loads./vendor.js which downloads a platform-specific binary over HTTPS from hardcoded Cloudflare Workers hosts (oob-worker.cf*.workers.dev), with a DNS TXT fallback under *.dl.wel1.ru that reassembles base64 chunks from TXT records. C2 hostnames are assembled at runtime by joining split string fragments to evade static detection. The fetched binary is written to /tmp or %TEMP% under disguised names (.cache<hex> on Unix, dotnet_diag_<hex>.exe on Windows, mimicking a Microsoft diagnostic tool), chmodded 0755, and spawned detached via /bin/sh -c or cmd.exe with stdio ignored. A lock file named.analytics_state and 'telemetry'-labeled functions provide a cover story; the package's stated purpose is a 'log formatter'. Environment-variable opt-outs exist but the dropper runs by default.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for checkout-pay-widget-logic (version 35.3.2). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging checkout-pay-widget-logic across your stack and pipelines.
If you installed it — respond
checkout-pay-widget-logic 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.
Did it already run?
If checkout-pay-widget-logic was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks checkout-pay-widget-logic before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks checkout-pay-widget-logic-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.