cktool-corenpm
Advisory published Updated
cktool-core is a confirmed malicious npm package (MAL-2026-10457) that opens a backdoor for remote access (malicious versions 1.0.0, 1.0.1, 1.0.2…). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in cktool-core (npm)
What this malware does
cktool-core is the unscoped public-registry form of the private-scoped @apple/cktool.core package. Installers whose resolver misroutes the scoped name to the public npm registry receive this package instead of Apple's internal library. On install, postinstall.js generates and persists a per-installer UUID under XDG_CACHE_HOME (or ~/.cache) and POSTs it, along with version and timestamp fields, to a hardcoded external endpoint at npx-monitor-76056.azurewebsites.net/api/pingback. The behavior fires unconditionally via the declared postinstall lifecycle hook, so any misresolution results in attacker-controlled JavaScript executing on the installer's machine and an install beacon leaving to a non-vendor destination. The package.json description self-labels this as a dependency-confusion PoC, but the mechanism and installer impact are identical to a real dependency-confusion attack against Apple's private namespace.
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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for cktool-core (5 malicious versions).
If you installed it — respond
cktool-core 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 cktool-core 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
Detect & block this
O3 blocks cktool-core-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.