MythicRatatoskr: An Yggdrasil-enabled backdoor deployed in a UAC-0099-Sandworm collaboration

ESET researchers uncover MythicRatatoskr – a previously unknown Go-based backdoor hiding its C&C server inside the Yggdrasil mesh network – that paved the way for a destructive attack against a Ukrainian grain firm

Published 23-Oct-2026 11:26 UTC · First seen 23-Oct-2026 11:25 UTC

Sources

• ESET WeLiveSecurity · 22-Oct-2026