Welcome to BlackFile: Inside a Vishing Extortion Operation
Written by: Austin Larsen, Tyler McLellan, Genevieve Stark, Dan Ebreo
Introduction
Google Threat Intelligence Group (GTIG) has continued to track an expansive extortion campaign by UNC6671, a threat actor operating under the "BlackFile" brand, that targets organizations via sophisticated voice phishing (vishing) and single sign-on (SSO) compromise. By leveraging adversary-in-the-middle (AiTM) techniques to bypass traditional perimeter defenses and multi-factor authentication (MFA), UNC6671 gains deep access to cloud environments. The group primarily targets Microsoft 365 and Okta infrastructure, leveraging Python and PowerShell scripts to programmatically exfiltrate sensitive corporate data for subsequent extortion attempts. This post details UNC6671’s attack lifecycle and provides defenders with actionable guidance to detect and mitigate these identity-centric threats.
Since emerging in early 2026, UNC6671 has maintained a high operational cadence. GTIG assesses that the group has targeted dozens of organizations across North America, Australia, and the UK.
GTIG previously highlighted UNC6671 as a distinct cluster in a ...
Copyright of this story solely belongs to google.com. To see the full text click HERE
