MAL-2026-17219 Malicious code in nebula-sdk (npm)

The preinstall.cjs lifecycle script embeds a base64-encoded, zlib-compressed Windows PE (~257KB) as a string literal. On npm install, the script decodes and decompresses the blob, writes the resulting executable to %LOCALAPPDATA%\Microsoft\Conhost\conhost.exe (masquerading as the legitimate Windows conhost binary), and spawns it detached with stdio ignored and windowsHide set to true, executing attacker-controlled native code on the installer's Windows machine with no user interaction. Decoded payload strings reference github.com/syskiel/kntrat-e and the IP 65.87.7.132, consistent with a native RAT-family tool. The package's advertised purpose is an AI SDK; a bundled native Windows executable dropped at install time is unrelated to that purpose and is delivered through multi-layer obfuscation (base64 + zlib + string-literal embedding) inside the lifecycle hook.

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.