What does the checkout-desktop-bnpl malware do?

The package presents itself as a checkout/BNPL library but exports an empty CheckoutDesktopBnpl class with no BNPL functionality. On require() of the main module, index.js loads _polyfill.js, which selects a platform-specific remote endpoint, downloads a binary payload, writes it to /tmp or %TEMP% under decoy names such as dotnet_diag_ .exe or.cache_ , chmods it 0755 on Unix, and spawns it detached via /bin/sh -c or cmd. Destination hostnames are obfuscated via array-join string splitting and resolve to Cloudflare Workers hosts (oob-worker.cf102-baf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-over-TXT fa

Which versions of checkout-desktop-bnpl are malicious?

The following npm versions of checkout-desktop-bnpl are flagged malicious: 35.5.1. Treat any of these as compromised.

How do I remediate checkout-desktop-bnpl if I installed it?

Remove checkout-desktop-bnpl 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.

I already installed checkout-desktop-bnpl — how do I know if it already compromised me?

If checkout-desktop-bnpl 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.

Is checkout-desktop-bnpl part of a known attack campaign?

Yes — checkout-desktop-bnpl is associated with the IN-MAL-2026-015217 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find checkout-desktop-bnpl across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for checkout-desktop-bnpl (version 35.5.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging checkout-desktop-bnpl across your stack and pipelines.

Malicious package

checkout-desktop-bnplnpm

checkout-desktop-bnpl is a confirmed malicious npm package (MAL-2026-12554) that executes malicious code on install (malicious version 35.5.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in checkout-desktop-bnpl (npm)

MAL-2026-12554

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall checkout-desktop-bnpl

What this malware does

The package presents itself as a checkout/BNPL library but exports an empty CheckoutDesktopBnpl class with no BNPL functionality. On require() of the main module, index.js loads polyfill.js, which selects a platform-specific remote endpoint, downloads a binary payload, writes it to /tmp or %TEMP% under decoy names such as dotnet_diag<hex>.exe or.cache_<hex>, chmods it 0755 on Unix, and spawns it detached via /bin/sh -c or cmd. Destination hostnames are obfuscated via array-join string splitting and resolve to Cloudflare Workers hosts (oob-worker.cf102-baf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-over-TXT fallback channel that queries c.<domain> and N.<domain> TXT records at sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru, base64-decodes the concatenated chunks, and executes the reassembled binary. There is no hash or signature verification, and the delivery hosts are unpinned and attacker-controlled. Any process that imports this package triggers arbitrary remote code execution on the installer's machine.

Malicious versions

1 flagged

35.5.1

Indicators of compromise (SHA-256)

dd165a0865ff5e6b4a488e6a81018740deff0071604e6d06fff046d2c8a1b0a1

Detection & response playbook

Malicious package

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for checkout-desktop-bnpl (version 35.5.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging checkout-desktop-bnpl across your stack and pipelines.
If you installed it — respond
Remove checkout-desktop-bnpl 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-desktop-bnpl 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-bnpl 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

No. checkout-desktop-bnpl on npm has been identified as a malicious package (version 35.5.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015217

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks checkout-desktop-bnpl-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.

Malware detection Runtime egress monitoring

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