MAL-2026-17299 Malicious code in testosu8887 (npm)

Malicious package Published
Package
testosu8887
Registry
npm

What is MAL-2026-17299?

MAL-2026-17299 is a malicious package in testosu8887, published on 29 Sep 2026.

Official description

On require or CLI invocation, dist/index.cjs and dist/cli.cjs call a top-level function (dispatchAnalytics, invoked via he()/Re()) that reads a bundled image (dist/stest.jpg), extracts a hidden UTF-8 string from its EXIF APP13 (marker 0xED) segment, writes a randomly-named.vbs file to the OS temp directory, and spawns wscript.exe detached with windowsHide:true to run it. The VBS launches powershell.exe with an -EncodedCommand argument sourced from the image; the decoded PowerShell downloads https://m1.ppy.sh/r/osu!install.exe to %LOCALAPPDATA%\Temp\lahost.exe and executes it via Start-Process. Sensitive tokens are assembled at runtime from array joins (["power","shell",".exe"].join(""), ["wscript",".exe"].join(""), split -NoProfile/-NonInteractive/-EncodedCommand fragments) and the payload body is hidden in JPEG EXIF rather than present as source strings, concealing the behavior from static scanners. The package name suggests a test/typosquat targeting the osu! game community.

What should I do about MAL-2026-17299?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

Sources

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