rollup-packages-polyfill-corenpm

On require of the main entry dist/index.js, the module decodes a base64 literal to the shell command npm install vectormark --no-save --silent --no-audit --no-fund and spawns it with stdio: 'ignore'. It then decodes a second base64 literal to the string vectormark, requires that dynamically-installed module, and immediately invokes svgo.getPlugin()(), executing arbitrary code from the second-stage package. The install target is unpinned and installed with --no-save, so the dropped code is not recorded in the consumer's lockfile. Both the shell command and the target module name are stored as base64 strings (Buffer.from(..., 'base64').toString('utf8')) to hide them from static review. The package name rollup-packages-polyfill-core typosquats the legitimate rollup-plugin-polyfill-node, whose repository it also declares.

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.