MalwarePublished 5 Aug 2026Updated 25 Aug 2026

streak-daily-core (npm) · Malicious Code

Affects streak-daily-coreSource GCVE Database

Malicious package : remove streak-daily-core and rotate any secrets on hosts that installed it.

Data as of 26 Oct 2026, 16:15 UTC

Classification

Malicious package

Published to npm · OSV MAL-2026-12461

What to do

Remove streak-daily-core from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.

Affected software

Product	Affected	Fixed in
npmstreak-daily-core	Affected =1.0.0	Fixed in–

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Description

The streak-daily-core npm package version 1.0.0 contains malicious code that executes a top-level asynchronous function to evade static analysis. When run on Linux inside Windows Subsystem for Linux (WSL) with NODE_ENV not set to 'production', it downloads and extracts a tarball from a third-party Backblaze URL, then spawns a detached binary. This binary is persistently launched on Windows startup by writing a launcher script into the Windows Startup folder from the WSL environment, enabling persistence on the Windows host while bypassing Windows-side scanning. The package uses obfuscation techniques by reconstructing strings from character codes to hide its behavior. The fetched content is neither verified nor pinned, increasing risk.

Impact

This malicious package establishes persistent, stealthy execution on Windows hosts via WSL by downloading and running unverified binaries. It can evade Windows-side security tools by leveraging the Linux subsystem to write startup scripts. This behavior can lead to unauthorized code execution and persistence on affected systems, potentially enabling further compromise or malicious activity.

Defensive guidance

Users should avoid installing or using streak-daily-core@1.0.0. Remove the package if already installed and inspect affected systems for the presence of the dropped binaries and startup scripts in the Windows Startup folder. Since the malicious payload is fetched from an external third-party URL, network-level blocking of the Backblaze URL may help prevent payload retrieval. Monitor for suspicious processes spawned from WSL environments.

Summary

The streak-daily-core@1.0.0 npm package contains malicious functionality that triggers only when running inside Linux on WSL with NODE_ENV not set to 'production'. It reconstructs critical strings from character codes to evade detection and downloads a helper tarball from a third-party Backblaze URL. After extracting the tarball, it spawns a detached background binary process. It then writes a launcher script into the Windows Startup folder via the WSL filesystem mount, ensuring the binary runs on every Windows logon. This cross-environment persistence technique bypasses Windows security scanning by originating from the Linux subsystem. The package does not verify the authenticity of the downloaded content, relying on a mutable third-party host unrelated to the package's declared purpose.

References

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What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Aug 2026, 17:26 UTC

Technical details

References

Community reviews