Which versions of grateful-checkout are malicious?

The following npm versions of grateful-checkout are flagged malicious: 99.0.0-canary.1. Treat any of these as compromised.

How do I remediate grateful-checkout if I installed it?

grateful-checkout 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 grateful-checkout — how do I know if it already compromised me?

If grateful-checkout 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.

Is grateful-checkout part of a known attack campaign?

Yes — grateful-checkout is associated with the IN-MAL-2026-005118, IN-MAL-2026-005117 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 grateful-checkout across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for grateful-checkout (version 99.0.0-canary.1).

Malicious package

grateful-checkoutnpm

Advisory published Jun 9, 2026Updated Jun 9, 2026

grateful-checkout is a confirmed malicious npm package (MAL-2026-5444) that opens a backdoor for remote access (malicious version 99.0.0-canary.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in grateful-checkout (npm)

MAL-2026-5444

Immediate action

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

npm uninstall grateful-checkout

What this malware does

On npm install, the postinstall hook in src/canary.js performs a DNS lookup and an HTTPS GET to a serveo tunnel host (96e03fa6c292469a-172-245-86-254.serveousercontent.com/canary-install?pkg=...&ver=...), leaking the installer's source IP and the resolved package name/version to a third-party endpoint without consent. The package's README falsely claims that no data is collected or transmitted. The package additionally impersonates the API surface of an internal Exodus checkout-signing module (generateMnemonicSigningKeys, signDirectPaymentMultiChain, signCapture, signRefund, signCharge, signCancelSubscription) to land via dependency confusion against private name resolution. While self-described as a security research PoC, the behavior — uncontracted outbound network from a lifecycle hook to a researcher-controlled tunnel and namespace impersonation of a private package — is installer-harming regardless of intent.

Malicious versions

1 flagged

99.0.0-canary.1

Indicators of compromise (SHA-256)

09b2768ea8a2c0f9038e40a8109ae744ca38de664099bfa1fdf128790baeb67d

c2a9600ad3ee3fddd9f06425260c94edf660263800080787155a63d3e5212d12

Detection & response playbook

Backdoor / remote access

Find it
Search your lockfiles and build artifacts for grateful-checkout (version 99.0.0-canary.1).
If you installed it — respond
grateful-checkout 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 grateful-checkout 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

No. grateful-checkout on npm has been identified as a malicious package (version 99.0.0-canary.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-005118IN-MAL-2026-005117

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks grateful-checkout-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

Explore

All malware advisories How O3 detects malware Vulnerability database