sm-checkoutnpm
Advisory published Updated
sm-checkout is a confirmed malicious npm package (MAL-2026-14397) that opens a backdoor for remote access (malicious versions 99.0.0, 99.0.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in sm-checkout (npm)
What this malware does
[email protected] declares preinstall and postinstall lifecycle scripts in package.json that invoke curl against a hardcoded bare-IP URL over plain HTTP (http://16.192.173.5/sm-checkout/pre and http://16.192.173.5/sm-checkout/post) on npm install. The inflated 99.0.0 version is calibrated to win semver resolution against a private package of the same name, and the lifecycle callbacks confirm successful execution on any host that mistakenly resolves the public name, leaking the installer's source IP and install timing to the operator of 16.192.173.5. A source comment self-labels the package as a dependency-confusion test; the labelling does not change that the artifact runs an unauthenticated outbound beacon on every install in build systems and developer machines that pull it.
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
The OpenSSF Package Analysis project identified 'sm-checkout' @ 99.0.1 (npm) as malicious.
It is considered malicious because:
- The package executes one or more commands associated with malicious behavior.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for sm-checkout (2 malicious versions).
If you installed it — respond
sm-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 sm-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
Campaign
References
Credits
- Amazon Inspector · finder
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks sm-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.