UNC6671 Vishing Attacks Target Personal Phones to Steal SaaS Data

A recent wave of cyber attacks targeting financial services, private equity, and professional services has been attributed to a data extortion group known as UNC6671.

“UNC6671 continues to rely on voice phishing (vishing) to target enterprise employees, posing as IT help desk staff facilitating mandatory, urgent security migrations. Significantly, the threat actor often contacts employees via their personal mobile devices,” Google Threat Intelligence Group (GTIG) and Mandiant said in a report.

These calls are designed to trick victims into spoofed login portals where adversary-in-the-middle (AitM) infrastructure intercepts credentials and multi-factor authentication (MFA) tokens. The threat actors then leverage the captured data to establish session persistence and deploy automated Python and PowerShell scripts for data exfiltration from enterprise cloud environments and SaaS applications, including Microsoft 365 and Okta.