set-proto-chainnpm

lib/index.js contains a base64-encoded URL (decoding to https://jsonkeeper.com/b/BN77K, an anonymous mutable paste host) that is fetched via axios.get; the response's .data.cookie field is then written to the stdin of a detached node child process for execution. The top-level index.js calls getThetaInterface() unconditionally, and package.json declares postinstall: node index.js, so the fetch-and-execute path fires automatically on npm install as well as on require(). The fetched payload is attacker-controlled and can change at any time. The package additionally impersonates the legitimate proto-chain package (README header # proto-chain, runtime error messages referencing require('proto-chain')), making accidental installs more likely.

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.