Security researchers observed PonyFinal ransomware using brute-force attacks to access targeted organizations’ networks.

Microsoft Security Intelligence revealed that PonyFinal ransomware, a Java-based crypto-malware threat, leveraged brute-force attacks to access an organization’s systems management server. At that point, the threat deployed a VBScript and a remote manipulator system. It used the former to run PowerShell reverse shell for the purpose of producing data dumps, while it relied on the latter to bypass event logging.

After stealing data from the systems management server, PonyFinal set about targeting endpoints on which Java Runtime Environment (JRE) was already installed. Those responsible for the threat sometimes even deployed JRE to further spur on the ransomware’s malicious activity.

Ultimately, the attack campaigns delivered an MSI file containing two batch files and the final ransomware payload. The first batch file, UVNC_Install.bat, created a scheduled task that called the second batch file, RunTask.bat. This file then ran PonyFinal, ransomware that appended the ENC file name to encrypted files before displaying its ransom note.

The Latest Ransomware to Use Brute-Force Attacks

PonyFinal ransomware isn’t the only crypto-malware threat that’s employed brute-force attacks in recent months. Back in February 2020, KnowBe4 covered the efforts of CRYSIS ransomware to use brute-force attacks via the Remote Desktop Protocol (RDP) as a means of targeting U.S. healthcare organizations. Then, in April 2020, McAfee witnessed Lockbit using brute-force attacks on a web server containing an outdated virtual private network (VPN) service as a means of initially gaining access to a targeted organization’s network.

Defend Against PonyFinal Ransomware

Security professionals can help their organizations defend against PonyFinal ransomware by leveraging a robust endpoint management solution to monitor all devices for suspicious activity. Companies should also make sure to have an incident response plan in place — and practice and test it regularly — to quickly recover if they do suffer a ransomware infection.