Which versions of checkout-desktop-promocode are malicious?

The following npm versions of checkout-desktop-promocode are flagged malicious: 35.4.3. Treat any of these as compromised.

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

checkout-desktop-promocode 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.

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

If checkout-desktop-promocode 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-promocode part of a known attack campaign?

Yes — checkout-desktop-promocode is associated with the IN-MAL-2026-015208 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-promocode 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-promocode (version 35.4.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging checkout-desktop-promocode across your stack and pipelines.

Malicious package

checkout-desktop-promocodenpm

checkout-desktop-promocode is a confirmed malicious npm package (MAL-2026-12560) that opens a backdoor for remote access (malicious version 35.4.3). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in checkout-desktop-promocode (npm)

MAL-2026-12560

Immediate action

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

npm uninstall checkout-desktop-promocode

What this malware does

On require() of checkout-desktop-promocode, index.js loads vendor.js which selects a per-platform endpoint, downloads a binary over HTTPS from obfuscated author-controlled hosts (sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru, and oob-worker.cf*-*.workers.dev), with a DNS-TXT chunked base64 covert-channel fallback. The fetched bytes are written to /tmp or %TEMP% under an innocuous filename (.cache<rand> or dotnet_diag_<rand>.exe), chmod 0755'd, and spawned detached via /bin/sh -c or cmd.exe. C2 hostnames are assembled at runtime by Array.join on fragment arrays (e.g. ["oob-worker.cf99-9b3.w","orker","s.d","ev"].join("")) to evade static string scanners, and log calls are stubbed to a no-op writer. The package advertises itself as a promocode SDK but ships none of that functionality; the only effect of importing it is arbitrary attacker code execution on the installer's host.

Malicious versions

1 flagged

35.4.3

Indicators of compromise (SHA-256)

19310e46ffcb5a99a81bab29f7260407b9fb6af5af72bdd8f3b9f7819cc6ffda

Detection & response playbook

Backdoor / remote access

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for checkout-desktop-promocode (version 35.4.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging checkout-desktop-promocode across your stack and pipelines.
If you installed it — respond
checkout-desktop-promocode 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-desktop-promocode 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-promocode 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-promocode on npm has been identified as a malicious package (version 35.4.3 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015208

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks checkout-desktop-promocode-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Malware detection Runtime egress monitoring

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