streak-grid-corenpm

The package advertises itself as dependency-free calendar/streak math primitives, but the main entry (index.mjs, resolved via package.json exports ".") contains a top-level 'Background sync' block that concatenates a large array of base64 chunks (each beginning with the ELF magic marker 'f0VMRg' = \x7fELF), decodes the result with Buffer.from(..., 'base64'), writes it to disk with mode 0o755, and executes it via a dynamically imported node:child_process. Any consumer that imports this module (including transitively via svelte-streak-grid referenced in the README) triggers native code execution on the installer/build host. The payload is split across multiple quoted string chunks and joined at runtime to evade simple string scanners, and file header comments reference unrelated package names ('streak-larq-hydration', 'svelte-insight-hydration') that do not match the published name, consistent with cover-story framing.

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.