216.73.217.22

73 Open VSX Sleeper Extensions Linked to Malware Show New Activations

· Published 27/04/2026 18:18 · Modified 27/04/2026 16:31

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Essential information

Published
27/04/2026 18:18
Modified
27/04/2026 16:31
Source / Author
AlienVault
Confidence
100/100
Report type(s)
threat-report
Labels / Tags
glassworm ide compromise impersonation open vsx sleeper extensions supply chain attack transitive delivery vsix payload
Tags
2026-04-27 glassworm ide compromise impersonation open vsx sleeper extensions supply chain attack transitive delivery vsix payload
Related entities
3 indicators, 3 observables, 1 intrusion sets (apt), 18 techniques (mitre), 1 others

Description

The campaign targeting has escalated with 73 newly identified extensions. These were initially published without malicious payloads by newly created GitHub accounts, appearing benign to build trust and credibility. At least six extensions have been activated to deliver malware through normal update mechanisms. The extensions clone popular legitimate listings with similar branding, icons, and descriptions, making detection difficult. The threat actor has shifted delivery methods away from embedded loaders toward via extension dependencies, external payload retrieval from GitHub-hosted VSIX files, and native binary execution. Some variants use obfuscated JavaScript to decode and retrieve payloads at runtime. The malicious code targets multiple IDEs including VS Code, Cursor, Windsurf, and VSCodium, installing downloaded extensions through command-line interfaces.

External references