MAL-2026-11035 Malicious code in streak-bucket-lib (npm)

The package advertises pure calendar/streak math but its main entry (index.mjs) schedules an async routine on module import via Promise.resolve().then(setTimeout(_i,0)). That routine dynamically imports fs/path/child_process/https using module names decoded from a _k lookup table through a reverse-then-hex unwrapper (const _d = s => Buffer.from(s.split('').reverse().join(''), 'hex').toString()), HTTP-GETs a remote archive to a hardcoded URL reconstructed from the same table, writes the response bytes to a per-user Windows AppData path, spawns an extractor on the archive, then invokes powershell with a script that constructs a WScript.Shell.lnk shortcut (TargetPath/WorkingDirectory/Save) in the user's Startup folder for persistence across reboots. Every operational string — module names, URL, AppData subpath components, extractor argv, and the powershell payload — is stored obfuscated in _k and only decoded at runtime. The behavior fires on any import 'streak-bucket-lib' with no lifecycle hook required. The declared calendar-math purpose has no need for network I/O, filesystem writes under AppData, child process execution, or powershell-authored startup shortcuts; the obfuscated destination table and dropper-plus-persistence shape identify this as a Windows stealer scaffold rather than a library.

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.