Spring Ring Campaign: How Attackers Weaponized Microsoft Teams for Enterprise Compromise
Between January and April 2026, cybersecurity researchers uncovered the Spring Ring operation, a coordinated social engineering campaign targeting over 150 employees across at least 10 organizations. Threat actors leveraged external Microsoft Teams accounts to impersonate IT help desk personnel, initiating voice phishing (vishing) calls that coerced victims into executing remote monitoring tools or custom malware. The most sophisticated variant escalated from vishing to NTLM relay attacks using PetitPotam exploits, targeting domain controllers for enterprise-wide compromise. The campaign demonstrates how attackers weaponize trusted collaboration platforms, exploiting the default "Chat with Anyone" feature to bypass traditional email-based security controls and establish direct communication channels with unsuspecting employees. This incident reflects the broader evolution of social engineering attacks, where collaboration tools have become the new frontier for cybercriminals. As organizations increasingly rely on SaaS platforms for daily operations, attackers are adapting their tactics to exploit the inherent trust users place in these environments, making identity-based attacks a critical emerging threat vector.
Kill Chain
