Cisco Talos Incident Response has observed attacks by Chaos, a new ransomware-as-a-service group conducting big-game hunting and double extortion attacks. The group uses spam flooding, voice-based social engineering, RMM tool abuse, and legitimate file-sharing software for data exfiltration. Their ransomware employs multi-threaded rapid selective encryption and anti-analysis techniques, targeting both local and network resources. Chaos is likely formed by former BlackSuit (Royal) gang members, based on similarities in encryption methodology, ransom note structure, and toolset. The group has impacted various business verticals, predominantly in the U.S., UK, New Zealand, and India. They use the '.chaos' file extension and demand ransoms around $300K, threatening data disclosure and DDoS attacks if not paid.
This intelligence report analyzes a sophisticated tool designed to disable endpoint security solutions, particularly EDR systems, on infected systems. The tool, known as AVKiller, has been observed in multiple ransomware attacks since 2022. It is heavily protected, targets various security vendors, and uses a driver with a compromised certificate to terminate processes and services. The report details the tool's characteristics, its connection to ransomware attacks, and provides examples of its use in specific ransomware families. Notably, the report highlights evidence of tool sharing and technical knowledge transfer among competing ransomware groups, suggesting a more complex ecosystem than previously thought.
