As per CISA (Cybersecurity and Infrastructure Assurance Agency) from US Govt.: “Ransomware is an ever-evolving form of malware designed to encrypt files on a device, rendering any files and the systems that rely on them unusable. Malicious actors then demand ransom in exchange for decryption. Ransomware actors often target and threaten to sell or leak exfiltrated data on authentication information if the ransom is not paid.”
In the recent past most of the government websites and the users are being targeted by the ransomware attackers. It is being observed that, the attacks may not be always for personal interest, rather it may lead to an organized data collection task group.
There are good number of Ransomware making rounds in the industry. Few to list are

Log4Shell is a severe, critical vulnerability affecting many versions of the Apache Log4j application. This vulnerability allows unauthenticated remote code execution. Log4Shell vulnerability is found in products of some of the most common technology vendors such as AWS, IBM, Cloudflare, Cisco, iCloud, Minecraft: Java Edition, Steam, and VMWare.

Log4j is critical it assessed that, most of the day-to-day applications are developed using Java and they will be vulnerable. Globally it is going to affect approximately 2.5 – 3 billion devices. Hence, it is very crucial for us to mitigate the risk.

Current mitigation is to remove JNDI Class files (Version 2.x), by replacing or removing references to context lookups (Version 2.x) and by removing JMSAppender for 1.x versions.