Spring Ring Campaign: How Vishing Attacks Weaponized Microsoft Teams in 2026
Between January and April 2026, the "Spring Ring" threat operation targeted over 150 Microsoft Teams users across 10+ organizations using sophisticated voice phishing (vishing) attacks. Attackers impersonated internal IT support staff through Teams chats, then conducted voice calls to trick employees into installing remote access tools or executing malware. The most advanced variant employed NTLM relay attacks targeting domain controllers for full infrastructure compromise, demonstrating a significant evolution from traditional email phishing to real-time social engineering through trusted collaboration platforms. This incident reflects the accelerating shift toward platform-native attacks as threat actors exploit the inherent trust users place in enterprise collaboration tools. With vishing attacks doubling in the first half of 2026 according to CrowdStrike data, organizations face an urgent need to reassess security controls around identity verification and SaaS platform governance as traditional perimeter defenses prove inadequate against socially-engineered compromise vectors.
Kill Chain