If this package is installed
Remove it, treat the machine (or CI runner) as compromised, and rotate every secret, token and key it could access — from a different, clean machine.
Details
Source: amazon-inspector (9b77c2c0dab050d3a675407d74b649c73bfc107da05191cf041fb66e0346073a)
package.json declares `optimize-regex` as a dependency (and devDependency) of itself, resolved via a plain-HTTP tarball URL at http://pack.nppacks.com/npm/optimize-regex — a host unrelated to the package's publisher and outside the npm registry. On `npm install`, npm fetches and installs whatever bytes that URL currently serves as the same package name, giving the operator of pack.nppacks.com full control over the code that ends up in the installer's node_modules. The URL is unpinned (no hash, no version), served over cleartext HTTP (mutable in transit as well as at the host), and the visible index.js is a near-verbatim clone of babel-plugin-transform-define with a package name and description that do not match that functionality — a decoy while the actual payload is delivered through URL-scheme dependency resolution.
Source: ghsa-malware (865196ef50a0163709b774b9a34fd0b7677fd8397d23ba40be7e82ecf2990232)
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.