Description

Recent campaigns involving the Trigona ransomware group reveal the use of a custom-built data exfiltration utility to enhance stealth and efficiency during attacks. Unlike traditional methods that rely on publicly available tools, attackers are now deploying proprietary malware to avoid detection and accelerate data theft operations. This evolution highlights a shift toward more controlled and covert pre-encryption stages in ransomware incidents. The newly observed tool, identified as uploader_client.exe, is a command-line utility designed specifically for exfiltrating sensitive data from compromised environments. It connects to a hardcoded remote server, enabling attackers to transfer stolen data directly without relying on commonly flagged tools such as Rclone or MegaSync. This approach allows threat actors to bypass traditional security detections that are tuned to identify known exfiltration utilities. By using a custom solution, attackers gain granular control over the data transfer process, improving both speed and operational security. Security researchers assess that this development indicates increased investment in proprietary tooling, particularly during critical phases of ransomware attacks such as data exfiltration prior to encryption. The use of such tools aligns with double-extortion tactics, where attackers first steal data and then encrypt systems, threatening public disclosure if ransom demands are not met. This makes early detection during the exfiltration phase increasingly difficult for defenders.