On a bi-weekly basis, FortiGuard Labs gathers data on ransomware variants of interest that have been gaining traction within our datasets and the OSINT community. The Ransomware Roundup report aims to provide readers with brief insights into the evolving ransomware landscape and the Fortinet solutions that protect against those variants.

This edition of the Ransomware Roundup covers the KageNoHitobito and DoNex ransomware.

Affected platforms: Microsoft Windows
Impacted parties: Microsoft Windows Users
Impact: Steals and encrypts victims' files and demands ransom for file decryption and not releasing the stolen data.
Severity level: High

KageNoHitobito Ransomware Overview

KageNoHitobito ransomware samples became available in late March 2024. As with most ransomware, this ransomware encrypts files on victims' machines and demands a ransom to decrypt them through dropped ransom notes. Although the group uses TOR to communicate with its victims, a data leak site is unavailable as it does not claim to have stolen any victims' information.

Infection Vector/Victimology

Information on the infection vector used by the KageNoHitobito ransomware threat actor is unavailable.

The KageNoHitobito ransomware samples were submitted to a publicly available file scanning service from several countries: Chile, China, Cuba, Germany, Iran, Lithuania, Peru, Romania, Sweden, Taiwan, the United Kingdom, and the United States. This suggests that the KageNoHitobito ransomware threat actor may have made the malware available on file-sharing services as fake software or game cheats and lured victims to these locations.

Attack Method

The KageNoHitobito ransomware is designed to encrypt files only on the local drive, not on networked drives. The files encrypted by the ransomware have a “.hitobito” extension.

Figure 1: Files encrypted by the KageNoHitobito ransomware.

It avoids encrypting files with the following file extensions:

The ransomware is designed not to continue if the current date of the compromised machine is 14 days after March 21, 2024.

Figure 2: KageNoHitobito ransomware code to not run beyond 14 days after March 21, 2024.

Figure 3: KageNoHitobito ransomware’s ransom note displayed on the victim’s desktop

Figure 4: Text version of the KageNoHitobito ransomware’s ransom note

KageNoHitobito is Japanese and can be translated as "shadow people." We could not associate the term "shadow people" with any popular culture, including Japanese anime, to which some threat actors are fixated.

The ransom note instructs victims to visit a TOR site that uses the AbleOnion chat platform and join a chat room. This site does not appear to be specific to the KageNoHitobito ransomware, as the ongoing group chat in both the designated chat room and the group chat at the time of our investigation is unrelated to ransom negotiations.

Figure 5: The TOR site that the KageNoHitobito ransomware uses for ransom negotiations

Figure 6: Ongoing chat at the time of our investigation

DoNex Ransomware Overview

DoNex is a relatively new, financially motivated ransomware group first reported in early March 2024. The file creation time of the samples is mid-February, so the ransomware may have been distributed prior to the date of the first report. All victims of the DoNex ransomware on the data leak site were added in February.

Infection Vector

Information about the infection vector used by the DoNex ransomware threat actor is unavailable. However, it is not likely to be significantly different from other ransomware groups.

Victimology

The DoNex ransomware’s data leak site on TOR listed five victims during our investigation. The organizations that were claimed to have been affected by the ransomware are located in Belgium, the Czech Republic, Italy, the Netherlands, and the United States.

Attack Method

The actions of DoNex ransomware are dictated by a configuration file set by the threat actor.

Figure 7: DoNex ransomware’s configuration file

Figure 8: Files encrypted by the DoNex ransomware

According to the <while_extens> section in the configuration file, DoNex ransomware avoids encrypting files with the following extensions:

It also avoids encrypting the following files listed in <white_files>:

The DoNex ransomware does not encrypt files in the following folders listed in <white_folders>:

It terminates the following processes listed in <kill_keep>:

It terminates the following services listed in <services>:

The ransomware is configured to delete shadow copies, making file recovery difficult.     

It then drops a ransom note labeled “Readme.[victim ID].txt} that demands contact via a TOR site, TOX chat, or email.

Figure 9: The DoNex ransomware’s ransom note

Figure 10: The DarkRace ransomware’s ransom note. Sentences also included in the DoNex ransomware’s ransom note are underlined in red.

Figure 11: The configuration file used by the DarkRace ransomware

Data Leak Site

During our research, the DoNex ransomware was operating a data leak site on TOR, which listed five victims in Europe and North America.

Figure 12: The DoNex ransomware’s data leak site

Since no new victims have been added since February 27th, the threat actor has likely already ceased operations and moved on.

Fortinet Protections

The KageNoHitobito and DoNex/DarkRace ransomware described in this report are detected and blocked by FortiGuard Antivirus as:

• MSIL/Filecoder.BCL!tr.ransom
• W32/Agent.AEUZ!tr.ransom

FortiGate, FortiMail, FortiClient, and FortiEDR support the FortiGuard AntiVirus service. The FortiGuard AntiVirus engine is a part of each of those solutions. As a result, customers who have these products with up-to-date protections are protected.

IOCs

KageNoHitobito and DoNex/DarkRace Ransomware File IOCs

FortiGuard Labs Guidance

Due to the ease of disruption, damage to daily operations, potential impact on an organization’s reputation, and the unwanted destruction or release of personally identifiable information (PII), etc., it is vital to keep all AV and IPS signatures up to date.

Since the majority of ransomware is delivered via phishing, organizations should consider leveraging Fortinet solutions designed to train users to understand and detect phishing threats:

The FortiPhish Phishing Simulation Service uses real-world simulations to help organizations test user awareness and vigilance to phishing threats and to train and reinforce proper practices when users encounter targeted phishing attacks.

Our FREE Fortinet Certified Fundamentals (FCF) in Cybersecurity training. The training is designed to help end users learn about today's threat landscape and will introduce basic cybersecurity concepts and technology.

Organizations will need to make foundational changes to the frequency, location, and security of their data backups to effectively deal with the evolving and rapidly expanding risk of ransomware. When coupled with digital supply chain compromise and a workforce telecommuting into the network, there is a real risk that attacks can come from anywhere. Cloud-based security solutions, such as SASE, to protect off-network devices; advanced endpoint security, such as EDR (endpoint detection and response) solutions that can disrupt malware mid-attack; and Zero Trust Access and network segmentation strategies that restrict access to applications and resources based on policy and context, should all be investigated to minimize risk and to reduce the impact of a successful ransomware attack.

As part of the industry's leading fully integrated Security Fabric, delivering native synergy and automation across your security ecosystem, Fortinet also provides an extensive portfolio of technology and human-based as-a-service offerings. These services are powered by our global FortiGuard team of seasoned cybersecurity experts.

FortiRecon is a SaaS based Digital Risk Prevention Service backed by cybersecurity experts to provide unrivaled threat intelligence on the latest threat actor activity across the dark web, providing a rich understanding of threat actors’ motivations and TTPs. The service can detect evidence of attacks in progress allowing customers to rapidly respond to and shut down active threats.

Best Practices Include Not Paying a Ransom

Organizations such as CISA, NCSC, the FBI, and HHS caution ransomware victims against paying a ransom partly because the payment does not guarantee that files will be recovered. According to a US Department of Treasury's Office of Foreign Assets Control (OFAC) advisory, ransom payments may also embolden adversaries to target additional organizations, encourage other criminal actors to distribute ransomware, and/or fund illicit activities that could potentially be illegal. For organizations and individuals affected by ransomware, the FBI has a Ransomware Complaint page where victims can submit samples of ransomware activity via their Internet Crimes Complaint Center (IC3).

How Fortinet Can Help

FortiGuard Labs’ Emergency Incident Response Service provides rapid and effective response when an incident is detected. Our Incident Readiness Subscription Service provides tools and guidance to help you better prepare for a cyber incident through readiness assessments, IR playbook development, and IR playbook testing (tabletop exercises).

Additionally, FortiRecon Digital Risk Protection (DRP) is a SaaS-based service that provides a view of what adversaries are seeing, doing, and planning to help you counter attacks at the reconnaissance phase and significantly reduce the risk, time, and cost of later-stage threat mitigation.