Ongoing Social Engineering Campaign Linked to Black Basta Ransomware Operators

Ongoing Social Engineering Campaign Linked to Black Basta Ransomware Operators

Co-authored by Rapid7 analysts Tyler McGraw, Thomas Elkins, and Evan McCann

Executive Summary

Rapid7 has identified an ongoing social engineering campaign that has been targeting multiple managed detection and response (MDR) customers. The incident involves a threat actor overwhelming a user's email with junk and calling the user, offering assistance. The threat actor prompts impacted users to download remote monitoring and management software like AnyDesk or utilize Microsoft's built-in Quick Assist feature in order to establish a remote connection. Once a remote connection has been established, the threat actor moves to download payloads from their infrastructure in order to harvest the impacted users credentials and maintain persistence on the impacted users asset.

In one incident, Rapid7 observed the threat actor deploying Cobalt Strike beacons to other assets within the compromised network. While ransomware deployment was not observed in any of the cases Rapid7 responded to, the indicators of compromise we observed were previously linked with the Black Basta ransomware operators based on OSINT and other incident response engagements handled by Rapid7.

Overview

Since late April 2024, Rapid7 identified multiple cases of a novel social engineering campaign. The attacks begin with a group of users in the target environment receiving a large volume of spam emails. In all observed cases, the spam was significant enough to overwhelm the email protection solutions in place and arrived in the user’s inbox. Rapid7 determined many of the emails themselves were not malicious, but rather consisted of newsletter sign-up confirmation emails from numerous legitimate organizations across the world.

Figure 1. Example spam email.

With the emails sent, and the impacted users struggling to handle the volume of the spam, the threat actor then began to cycle through calling impacted users posing as a me ..

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