Other threat group

UAT-9921

UAT-9921 is classified as other threat group.

Origin
China
Also known as
1

UAT-9921 is a China-nexus threat actor active since 2019, tracked by Cisco Talos. In 2026, they were observed deploying 'VoidLink', a sophisticated modular framework primarily targeting Linux systems (IoT, Critical Infrastructure). Unique characteristics include the use of AI-enabled IDEs for rapid development (ZigLang implant, GoLang backend), P2P mesh networking for C2, and advanced persistence via eBPF rootkits. They target Technology and Financial sectors exploiting Java serialization vulnerabilities (Apache Dubbo).

The group's reported origin is China.

Also known as: VoidLink Operator

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UAT-9921 · Threat actors · Dark Radar