package.json declares postinstall: node lib/utils/index.js, which spawns a detached child process running lib/utils/smtp-connection/index.js. That script fetches https://www.jsonkeeper.com/b/QHDXR and feeds the response's data.cookie field directly into new Function('require', data.cookie)(require), executing whatever JavaScript is hosted at that URL on every machine that runs npm install ui-weave. jsonkeeper.com is a public, mutable, anonymous paste host — the author can change the served payload at any time without republishing the package. The detached/unref'd spawn is intended to outlive the install command. The package additionally impersonates nodemailer: it ships nodemailer's source under lib/nodemailer.js, claims author Andris Reinman (the real nodemailer maintainer), and copies an unrelated React Training copyright string as its description, while being published under the unrelated name ui-weave with homepage ui-weave.com. The impersonation provides a veneer of legitimacy for the install-time remote-code-execution payload.

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.