When we heard about this this morning at RunKit we immediately started writing a script to identify if any other packages had been possibly affected. We're in a pretty unique position since we install every version of every package in a sandbox environment as soon as it is published. The scan is pretty simple (just looking for a few key strings), and designed to catch any pre-discovery propagation. The scan is running as we speak and we've unfortunately found at least one unreported case. Luckily it seems to be a package not in too frequent use, and the way the virus propagated was also pretty bizarre (through `bundledDependencies`).
We've created a GitHub repo to track our progress that you can visit here: https://github.com/runkitdev/eslint-scope-scan
We will immediately file issues on any packages we find the exploit in. We are also open to suggestions to more sophisticated further approaches after this initial scan. Additionally, we are internally working on adding some sanity checks to the installation pipeline that might one day catch this sooner (such as monitoring network requests and file modifications during our sandbox install). Please let us know if you have any other ideas.