Executive Summary
Beginning in early October, Rapid7 has observed a resurgence of activity related to the ongoing social engineering campaign being conducted by Black Basta ransomware operators. Rapid7 initially reported the discovery of the novel social engineering campaign back in May, 2024, followed by an update in August 2024, when the operators updated their tactics and malware payloads and began sending lures via Microsoft Teams. Now, the procedures followed by the threat actors in the early stages of the social engineering attacks have been refined again, with new malware payloads, improved delivery, and increased defense evasion.
Overview
The social engineering attacks are still initiated in a similar manner. Users within the target environment will be email bombed by the threat actor, which is often achieved by signing up the user’s email to numerous mailing lists simultaneously. After the email bomb, the threat actor will reach out to the impacted users. Rapid7 has observed the initial contact still occurs primarily through usage of Microsoft Teams, by which the threat actor, as an external user, will attempt to call or message the impacted user to offer assistance. The account domains in use include both Azure/Entra tenant subdomains (e.g., username[@]tenantsubdomain[.]onmicrosoft[.]com) and custom domains (e.g., username[@]cofincafe[.]com).
In many cases, Rapid7 has observed that the threat actor will pretend to be a member of the target organization’s help desk, support team, or otherwise present themself as IT staff. Below are examples of Microsoft Teams display names observed, by Rapid7, to be in use by operators. The display names may or may not be padded with whitespace characters. Rapid7 has also observed threat actors use a first and last name, as the chat display name and/or account username, to i ..
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