Recent variants of Sodinokibi accounted for scaling issues as the ransomware family steadily moves to target large enterprises.

According to Coveware, some of the most recent samples of Sodinokibi used an encryption process that created multiple victim ID profiles and encrypted file extensions and corresponding Tor pages where victims could receive payment instructions. This is similar to when Coveware previously observed GandCrab integrating with exploit kits and leveraging unique IDs.

However, this technique backfired in another attack campaign observed by Coveware researchers in February — as the number of victim IDs grew dramatically, issues arose for both victims and operators of GandCrab alike.

Unlike GandCrab, Sodinokibi ransomware accounted for these challenges by enabling a single tool to decrypt an entire network of extensions, regardless of the number of victim IDs. With this technique, samples of Sodinokibi successfully infected larger networks and demanded higher ransom amounts than the typical GandCrab infection in the spring of 2019.

Understanding Sodinokibi’s Zero-Day Exploit

Sodinokibi ransomware made headlines in April 2019 when Cisco Talos observed an attack campaign leveraging CVE-2019-2725, a previously undisclosed vulnerability affecting Oracle WebLogic, to distribute the threat. Most of the time, ransomware actors use “softer” vulnerabilities such as phishing attacks and unsecured remote desktop protocol (RDP) configurations to install their payloads.

The fact that Sodinokibi’s handlers chose to use a zero-day exploit and invest so much in their malware’s Tor sites suggested to Coveware that the ransomware will become a “popular choice” among digital criminals in the future, according to their most recent Sodinokibi report.

How to Defend Against Ransomware

Security professionals can help their organizations defend against threats like Sodinokibi by using test phishing engagements to prepare employees for social attacks commonly used by threat actors to distribute ransomware. Organizations should also create a layered defense strategy that employs data backups, anti-malware tools and additional employee security awareness training in the fight against ransomware.