GlassWorm Malware Discovered in Three VS Code Extensions with Thousands of Installs

GlassWorm has reappeared in three VS Code extensions, all still available for download, in what researchers describe as a continued campaign to weaponise the VS Code ecosystem. The extensions cited are ai-driven-dev with 3,402 downloads, adhamu[.]history-in-sublime-merge with 4,057 downloads, and yasuyuky[.]transient-emacs with 2,431 downloads.

GlassWorm first surfaced in late October, and Open VSX said it identified and removed all malicious extensions, rotating or revoking the associated tokens as of 21 October 2025. In their analysis, researchers note that the malware uses invisible Unicode characters to hide its code and employs pilfered credentials to compromise additional extensions, creating a self-replication, worm-like spread.

The attacker is described as Russian-speaking, and a browser extension C2 framework named RedExt is used as part of the infrastructure. According to Koi Security, the latest findings show fresh activity linked to the campaign, including a new C2 endpoint for the next-stage payload and victims spanning multiple regions, with a major government entity among those affected.