The five-day job: A BlackByte ransomware intrusion case study

July 6, 2023
As ransomware attacks continue to grow in number and sophistication, threat actors can quickly impact business operations if organizations are not well prepared. In a recent investigation by Microsoft Incident Response (previously known as Microsoft Detection and Response Team – DART) of an intrusion, we found that the threat actor progressed through the full attack chain, from initial access to impact, in less than five days, causing significant business disruption for the victim organization.

Our investigation found that within those five days, the threat actor employed a range of tools and techniques, culminating in the deployment of BlackByte 2.0 ransomware, to achieve their objectives. These techniques included:

Exploitation of unpatched internet-exposed Microsoft Exchange Servers
Web shell deployment facilitating remote access
Use of living-off-the-land tools for persistence and reconnaissance
Deployment of Cobalt Strike beacons for command and control (C2)
Process hollowing and the use of vulnerable drivers for defense evasion
Deployment of custom-developed backdoors to facilitate persistence
Deployment of a custom-developed data collection and exfiltration tool

The five-day job: A BlackByte ransomware intrusion case study
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