Researchers at Cisco have identified millions of machines that could become infected with file-encrypting ransomware due to out-of-date software.
Ransomware attacks aimed at organizations have been increasingly common and malicious actors have been trying to come up with new methods to make their operations more profitable.
Cybercriminals behind “Samsam,” a piece of ransomware whose existence came to light in March, have been compromising out-of-date JBoss application servers and leveraging them to access other machines on the network in an effort to get them infected. Samsam, also known as Samas, is believed to be the ransomware that recently encrypted data on computers belonging to MedStar hospitals in Maryland.
Attackers have been using JexBoss, an open source tool designed for finding and exploiting vulnerabilities in JBoss application servers, to gain access to the targeted network and encrypt files on Windows machines using Samsam ransomware.
Cisco Talos reported on Friday that it conducted an Internet scan and discovered roughly 3.2 million at-risk machines. A search for already compromised machines on which ransomware could be deployed at any minute revealed more than 2,100 backdoors across 1,600 IP addresses associated with governments, schools, aviation companies and other types of organizations.
Some of the compromised systems had been running the Destiny school library management system from Follett. The vendor has been working on patching vulnerable systems and removing any backdoors they may have been infected with.
Cisco reported identifying more than one backdoor on many of the compromised systems, which suggests that the infected machines had been targeted several times by different threat actors. The list of webshells found by researchers includes mela, shellinvoker, jbossinvoker, zecmd, cmd, genesis, sh3ll and possibly Inovkermngrt and jbot.
“With around 2100 servers affected, there are a lot of stories about how this happened. But a consistent thread in them all is the need to patch. Patching is a key component to software maintenance. It is neglected by both users and makers of the software far too often,” Cisco’s Alexander Chiu explained in a blog post. “Failures anywhere along the chain will ensure that this type of attack remains successful. With the addition of ransomware, the potential impacts could be devastating for small and large businesses alike.”
Cisco has advised administrators who find webshells on their servers to disable external access to the infected machine to keep attackers out. Then, they should either completely reinstall the system and ensure that all software is up to date, or restore the system to a previous point (before it was compromised) and patch all vulnerable applications.
Related: Why Ransomware is Winning – and How to Turn the Tide