In October 2024, Interlock claimed to have attacked several organizations, including Wayne County, Michigan, which is known for its cyberattacks. Ransomware is characterized by the fact that the encrypted data is encrypted by an encryptor specifically designed for the FreeBSD operating system, an operating system widely used in critical infrastructure. 

In late September 2024, a unique approach was used to launch the operation, which uses an encryptor specifically designed for FreeBSD. Interlock has already attacked several organizations, including Wayne County in Michigan, which was attacked in October 2024 by a cybercriminal organization called Interlock.

During the Interlock attack, the attacker breaches corporate networks, steals data from them, spreads to other devices laterally, and encrypts their files. In addition to using double-extortion tactics, they threaten to leak stolen data unless ransom demands of hundreds of thousands to millions of dollars are met. A particular feature of Interlock is its focus on FreeBSD encryptors, which makes it uniquely different from other ransomware groups that target Linux-based VMware ESXi servers. 

FreeBSD is a widely used operating system and a prime target of malicious hackers who want to disrupt critical infrastructure and extort victims for a large sum of money. This FreeBSD encryptor was developed specifically for FreeBSD 10.4, and it is a 64-bit ELF executable that is designed specifically for FreeBSD. 

Although the sample was tested on both Linux and FreeBSD virtual machines, the execution of the code was problematic since it failed to work in controlled environments. A ransomware attack is a sophisticated type of malware that seeks to seize control of data, effectively denying access to files and systems. 

In this malicious software, advanced encryption techniques are employed to render data inaccessible without a unique decryption key exclusive to the attackers. There is usually a ransom payment, usually in cryptocurrency, which victims are required to make to restore access and secure the attackers' privacy. Security experts Simo and MalwareHunterTeam, who analyzed ransomware samples, revealed the attack's initial details and the attackers' anonymity. 

As with most ransomware attacks, Interlock follows a typical pattern: the attackers breach corporate networks, steal sensitive information, copy the data and spread to other devices, encrypting files as they are copied. In addition to using double-extortion tactics, they also threaten to leak stolen data unless the victim pays a ransom of thousands to millions of dollars, depending on the size of the ransom. It is also the focus on FreeBSD that makes Interlock particularly unique, which illustrates why this operating system has a vital role to play in critical systems. 

A major characteristic of Interlock's ransomware is its direct targeting of FreeBSD servers, which are common in web hosting, mail servers, and storage systems. Unlike other ransomware groups that usually target Linux-based VMware ESXi servers, Interlock targets FreeBSD servers. Besides being integral to critical operations, these systems serve as lucrative targets for attackers. 

In spite of FreeBSD's popularity and essential services, its focus can also pose a challenge to cybersecurity professionals. In the initial testing phase of FreeBSD's encryptor, which was explicitly compiled for the FreeBSD 10.4 operating system, it did not prove easy to execute both the FreeBSD and Linux encryptors in controlled environments, since the encryptor is written as a 64-bit ELF executable. However, despite these hurdles, Trend Micro researchers discovered further samples of the encryption, confirming its functionality, strategic focus and capabilities. 

As a reminder of the vulnerabilities within critical infrastructure, Interlock has launched its attacks to increase awareness. The fact that it uses FreeBSD's own encryptor is a troubling development in ransomware tactics. This emphasizes the importance of strong security measures to safeguard against this increasing threat. To minimize the risk and impact of such cyberattacks, organizations should prioritize improving their security strategies.

It is recommended by Ilia Sotnikov, Security Strategist at Netwrix, that organizations use multi-layered security measures to prevent initial breaches, including firewalls and intrusion detection systems, as well as phishing defences. Interlock, a ransomware group that has been attacking organizations worldwide lately, has used an unusual approach of creating an encryptor to attack FreeBSD servers as a means of stealing data. 

Generally, FreeBSD is considered to be one of the most reliable operating systems available, so it is commonly used for critical functions. For example, the web host, mail server and storage systems are all potential targets for attackers, all of which can pose a lucrative threat. According to Sotnikov, depending on their configuration, a server may or may not be directly connected to the Internet, depending on their function. 

The security team should invest in defence-in-depth so that a potential attack is disrupted as early as possible so that every subsequent step for the attacker will be more difficult, and so that potentially harmful activity can be identified as fast as possible with the help of monitoring tools. Considering that the adversary is likely to access the FreeBSD server from inside the network, it might be a good idea to minimize standing privileges by implementing the zero trust principle, which means that a user should only have access to the permissions needed to achieve their tasks, sotnikov suggested.