UNC3966 is a threat actor group tracked by Mandiant. In an intrusion documented in March 2023, UNC3966 received access to a victim network initially compromised by the group UNC961. UNC3966 primary motivations remain unclear. During the intrusion, the group was observed collecting and exfiltrating victim data. While a ransom note was also discovered, UNC3966 did not appear to deploy ransomware encryption software and did not appear to demand a ransom payment.^{[Mandiant UNC961 March 23 2023]}