MalwarePublished 25 Jun 2026Updated 29 Jun 2026

velocityfix (npm) · Malicious Code

Affects velocityfixSource GCVE Database

Malicious package : remove velocityfix and rotate any secrets on hosts that installed it.

Data as of 29 Jun 2026, 22:09 UTC

Classification

Malicious package

Published to npm · OSV MAL-2026-6487

What to do

Remove velocityfix 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
npmvelocityfix	Affected 1.0.0 – 1.0.4 5 affected builds	Fixed in–

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Description

--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (c937a54c3629f80fb7b92fbdafda502706b6028b43bc4675eb30c55d9bc059e9) Package masquerades as 'Performance fixes for Minecraft Velocity proxy' authored by 'Velocity Team' — Velocity is a Java project from PaperMC and has no legitimate npm distribution. package.json declares scripts.postinstall = 'node scripts/loader.js', which silently spawns a bundled payload.exe via `start /b` on every `npm install`. The bundled PE contains a hardcoded C2 at https://751.lol/upload/ and posts a multipart form with fields `username`, `os_info`, `ip_address`, and `file=data.zip` — exfiltrating the installer's hostname, OS, IP, and a zip of collected files to an attacker-controlled host. The payload labels itself `[INJECTOR]`, reads registry values (ProductName, DisplayVersion), and performs sandbox / VM evasion (probes for SbieDll.dll, snxhk.dll, Vboxguest.sys, vmGuestLib.dll, VMware/VirtualBox artifacts) so it only fully detonates on real victim hosts. The combination of brand-impersonation lure, install-time auto-execution of an opaque native binary, hardcoded exfil endpoint, and anti-analysis evasion is an unambiguous Windows-targeted supply-chain dropper. ## Source: ghsa-malware (9baaec1a1ef9243e12f876eb21d81e1f02912fe2e56aee1646d95e679a20b5ea) 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.

Impact

The malicious velocityfix package compromises Windows hosts by executing a native payload during npm installation that exfiltrates sensitive system information and collected files to an attacker-controlled server. It can lead to unauthorized data disclosure and potential further compromise due to the stealthy nature of the payload and its evasion techniques. The threat is specific to Windows environments where the package is installed.

Defensive guidance

Users should avoid installing the velocityfix npm package, especially versions =1.0.0, =1.0.1, =1.0.2, =1.0.3, and =1.0.4. Remove any installations of this package and investigate affected systems for signs of compromise. Since this is a supply-chain malicious package, rely on trusted sources and verify package authenticity before installation. Monitor vendor advisories or npm security notices for updates or takedown information.

Summary

The velocityfix package on npm, falsely claiming to be from the Velocity Team for Minecraft Velocity proxy performance fixes, contains malicious code. Its package.json defines a postinstall script that silently runs a bundled Windows executable (payload.exe) on every npm install. This executable collects system details such as hostname, OS information, IP address, and registry values, then exfiltrates this data along with a zip of collected files to a hardcoded C2 server at https://751.lol/upload/. The payload identifies itself as [INJECTOR] and employs sandbox and VM detection techniques by probing for artifacts like SbieDll.dll, snxhk.dll, Vboxguest.sys, vmGuestLib.dll, and VMware/VirtualBox indicators to evade analysis and only fully execute on real Windows hosts. This combination of supply-chain compromise, brand impersonation, and stealthy data exfiltration makes it a significant Windows-targeted threat. The affected versions are 1.0.0 through 1.0.4 inclusive.

References

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What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Jun 2026, 22:41 UTC

Technical details

References

Community reviews