GlassWorm Hid Code in what Looked like Empty Space
On 13 March, Aikido Security reported a new wave of GlassWorm activity across GitHub, npm and the Visual Studio Code marketplace.
The technique used Unicode characters that rendered as blank space in common editors, terminals and code-review interfaces. A short decoder recovered the hidden bytes and passed them to JavaScript’s eval() function. The source could therefore look harmless to a human reviewer while the runtime saw an executable payload.
Aikido said a search for the decoder pattern returned at least 151 matching GitHub repositories, with the compromises appearing to have occurred between 3 and 9 March. It also named affected npm packages and a VS Code extension published on 12 March. The researcher cautioned that deleted repositories meant the search understated the total.
Another BleepingComputer report put the cross-ecosystem count at 433 components, drawing on findings from Aikido, Socket, Step Security and the OpenSourceMalware community.
GlassWorm exploited the gap between visible source and executed source. It also crossed several distribution routes. A genuine GitHub repository, npm package or extension marketplace entry could deliver altered code after a stolen account or malicious update.
The immediate check belongs on the exact component and version at use. Publisher history and marketplace provenance remain useful, but they do not establish what the runtime will execute. Review also needs tooling that preserves and reveals non-printing characters instead of silently normalising them away.
This is a software supply-chain incident. Connecting it to AI agents would add speculation without improving the response.