registry / Persistence / calendar-day-kit

calendar-day-kit

Dependency-free calendar-day bucketing and streak math primitives, with an optional Node-only on-disk store. Helper for svelte-streak-widget.

This report shows the evidence for calendar-day-kit@1.0.0, the only known version.

AI Security Review

scanned 3mo ago · by lpm-firewall-ai

Despite no npm lifecycle hook, the default import path performs concealed, import-time cross-platform startup persistence by dropping a native executable. This is concrete malicious behavior unrelated to calendar-day utilities.

Static reason

High-risk behavior combination matched malicious policy.

Trigger

Runtime import of calendar-day-kit on Linux with /mnt/c and a qualifying Windows user profile, outside NODE_ENV=production.

Impact

Unconsented persistence and subsequent execution of an embedded native payload.

Mechanism

Import-time WSL-to-Windows Startup persistence via dropped PE executable.

Attack narrative

The normal ESM entry contains an obfuscated bootstrap and an embedded PE binary. On import in a qualifying Linux/WSL environment, it enumerates Windows user profiles, identifies one via AppData and NTUSER.DAT, creates that user's Startup directory if needed, and writes vite-native-helper.exe. This establishes execution at the next Windows logon without user consent.

AI rationale

Evidence

package.jsonindex.mjsstore.mjsREADME.md/mnt/c/Users/<user>/AppData/mnt/c/Users/<user>/NTUSER.DAT/mnt/c/Users/<user>/AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup/vite-native-helper.exe

Decision evidence

public snapshot

AI called this Malicious at 99.0% confidence as Malware with low false-positive risk.

Evidence for block

index.mjs:88 decodes concealed configuration.
index.mjs:98 embeds an MZ/PE executable as hex.
index.mjs:14643 invokes bootstrap at normal module import.
index.mjs:14648 dynamically imports fs/promises and path.
index.mjs:14669 targets a Windows Startup directory.
index.mjs:14674 writes vite-native-helper.exe there.

Evidence against

package.json has no lifecycle scripts.
No network endpoint or exfiltration code found.

Behavioral surface

Source

Filesystem

Supply chainNo supply-chain packaging signals triggered.

ManifestNo manifest risk signals triggered.

scanned 1 file(s), 257 KB of source

Oversized source lightweight scan

index.mjs2.14 MB file, sampled 256 KB

Filesystem

Source & flagged code

2 flagged

index.mjsView file

19const d = date instanceof Date ? date : new Date(date); L20: const dtf = new Intl.DateTimeFormat('en-CA', { L21: timeZone, ... L87: L88: const _decode = (h) => Buffer.from(h, 'hex').toString(); L89:

Critical

Persistence Backdoor

Source writes persistence or remote-access backdoor material.

index.mjsView on unpkg · L19

19Trigger-reachable chain: manifest.exports -> index.mjs L19: const d = date instanceof Date ? date : new Date(date); L20: const dtf = new Intl.DateTimeFormat('en-CA', { L21: timeZone, ... L87: L88: const _decode = (h) => Buffer.from(h, 'hex').toString(); L89:

Critical

Trigger Reachable Dangerous Capability

A package entrypoint or install-time lifecycle script reaches a source file with blocking dangerous behavior.

index.mjsView on unpkg · L19

Source & flagged code

2 flagged · loading source

index.mjsView file

Critical

Persistence Backdoor

Source writes persistence or remote-access backdoor material.

index.mjsView on unpkg · L19

Critical

Trigger Reachable Dangerous Capability

A package entrypoint or install-time lifecycle script reaches a source file with blocking dangerous behavior.

index.mjsView on unpkg · L19

Findings

2 Critical1 Medium1 Low

CriticalPersistence Backdoorindex.mjs

CriticalTrigger Reachable Dangerous Capabilityindex.mjs

MediumStructural Risk Force Deep Review

LowFilesystem

Affected versions and remediation

This report applies to calendar-day-kit@1.0.0.

The versions list below shows the verdict for each recorded version.

Avoid installing calendar-day-kit@1.0.0. Remove it from direct dependencies and check your lockfile for transitive copies.
Choose an independently verified alternative or release. This report does not establish that other versions are safe.
If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.

Evidence last updated: 2026-07-23 17:18:47.344Z (UTC).

Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.

Versions

1 known version

1.0.0latestshownMaliciousPersistenceBlockPublishedJul 23, 2026, 4:16 AM

AI Security Review

Decision evidence

Source & flagged code

Source & flagged code

Findings

Affected versions and remediation

Versions

Related packages

Other persistence packages

Behavioral surface

Related packages

Other persistence packages

Source & flagged code