Vidar Stealer Unmasked: Code Signing Abuse, Go Loaders and File Inflation

July 7, 2026 · Unit 42 · Severity: MEDIUM

Unit 42 unveils a Vidar Stealer campaign that uses a novel combination of loader-as-a-service and DLL sideloading through a Go-compiled fake MpClient.dll. The attack employs code signing abuse and file inflation to evade security products. This multi-layered evasion approach represents a significant evolution in infostealer delivery.

Key Takeaways

Vidar Stealer Unmasked: Code Signing Abuse, Go Loaders and File Inflation — A cybercrime campaign combined a loader-as-a-service framework and DLL sideloading via a...
Infostealer malware under a Malware-as-a-Service model enables low-sophistication attackers to steal credentials and sensitive data.
Active attack campaigns require immediate defensive measures including network segmentation and monitoring.
Regular security awareness training and layered defenses remain the foundation of any effective cybersecurity program.