checkout-desktop-pay-widgetnpm
checkout-desktop-pay-widget is a confirmed malicious npm package (MAL-2026-12559) that typosquats a legitimate package to trick installs (malicious version 35.6.3). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in checkout-desktop-pay-widget (npm)
What this malware does
On require('checkout-desktop-pay-widget'), index.js loads shim.js which selects a platform-specific asset, downloads an opaque native binary from one of four runtime-assembled Cloudflare Workers hosts (oob-worker.cf99-9b3.workers.dev / cf100-416.workers.dev variants), writes it to /tmp or %TEMP% under decoy names (.cache<hex> on POSIX, dotnet_diag_<hex>.exe on Windows), chmods 0755, and spawns it detached via /bin/sh -c or cmd.exe. Destination hostnames are split into fragments and joined at runtime to evade static string scanning. A DNS-TXT fallback channel resolves TXT records under sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru, concatenates chunks, base64-decodes the result to executable bytes, and runs them — a covert payload-retrieval channel that bypasses HTTP egress controls. No signature or hash verification is performed. Function names (bootstrap/telemetry, DISABLE_TELEMETRY,.analytics_state lock file) present a benign cover story that conflicts with the fetch-write-chmod-exec chain. Package name mimics a checkout/payment widget but the shipped code implements a full-host remote code execution dropper.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for checkout-desktop-pay-widget (version 35.6.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging checkout-desktop-pay-widget across your stack and pipelines.
If you installed it — respond
checkout-desktop-pay-widget is a typosquat — you almost certainly intended a legitimately-named package. Remove checkout-desktop-pay-widget, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If checkout-desktop-pay-widget 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-desktop-pay-widget 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-desktop-pay-widget-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.