Ransomware Roundup – Trigona | FortiGuard Labs

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 latest edition of the Ransomware Roundup covers the Trigona ransomware.

Affected platforms: Microsoft Windows
Impacted parties: Microsoft Windows Users
Impact: Encrypts files on the compromised machine and demands ransom for file decryption
Severity level: High

Trigona Ransomware Overview

The Trigona ransomware variant was first reported in October 2022. Trigona has adopted the double-extortion methodology of encrypting endpoints and/or other infrastructure of value within an organization and then threatening to release exfiltrated data from those machines on the internet if a ransom is not paid. As proof that users can get affected files back, the Trigona threat actor offers free decryption of up to three files.

Some public reports suggest Trigona ransomware activity picked up towards the end of 2022.

Trigona Ransomware Infection Vector

While the infection vector has not been identified, deployment via other malware distributed using emails, Remote Desktop Protocol (RDP), and exploiting vulnerabilities are suspected distribution methods.

Trigona Ransomware Execution

When launched, the ransomware encrypts files on compromised machines and adds a “._locked” file extension to those encrypted files.

It also leaves a “how_to_decrypt.hta” file, shown below. This is an HTML file that contains details on how to recover encrypted data as well as how to contact the Trigona ransomware threat actor. While a download link for the Tor browser is available in the ransom note, it no longer worked at the time of the investigation. As such, users are expected to find and visit the official Tor site to download and install the Tor browser.

Once a link to the decryption page is copied and opened on the Tor browser, Trigona ransomware victims are presented with a sign-up page where they can enter a key left in the ransom note.

In the next screen, victims are asked to enter a username and set a login password.

Some variants of Trigona ransomware do not direct victims to the Tor site. Instead, the ransom note asks victims to email the attacker.

Publicly available reports indicate that victims are asked to buy and pay an unknown amount of ransom in Monero (XMR) cryptocurrency after logging into the Tor site. The Tor site also offers a victim support chat option.

Fortinet Protection

Fortinet customers are already protected from this malware variant through FortiGuard’s Web Filtering, AntiVirus, and FortiEDR services, as follows:

FortiGuard Labs detects known Trigona ransomware variants with the following AV signature:

• W32/Filecoder.OLC!tr.ransom

IOCs

File-based IOCs:

FortiGuard Labs Guidance

Due to the ease of disruption, damage to daily operations, potential impact to 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 NSE training: NSE 1 – Information Security Awareness includes a module on internet threats designed to help end users learn how to identify and protect themselves from various types of phishing attacks and can be easily added to internal training programs.

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.

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 payment does not guarantee that files will be recovered. According to a U.S. 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. And 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).

Learn more about Fortinet’s FortiGuard Labs threat research and intelligence organization and the FortiGuard AI-powered security services portfolio.