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Ransomware Defense Using the Wazuh Open Source Platform. Ransomware is malicious software designed to block access to a computer system or encrypt data until a ransom is paid. This cyberattack is one of the most prevalent and damaging threats in the digital landscape, affecting individuals, businesses, and critical infrastructure worldwide. A ransomware attack typically begins when the malware infiltrates a system through various vectors such as phishing emails, malicious downloads, or exploiting software vulnerabilities. Once activated, the malware encrypts files using strong cryptographic algorithms, rendering them inaccessible to the legitimate owner. The attackers then demand payment, usually in cryptocurrency like Bitcoin, in exchange for the decryption key. Modern ransomware variants have evolved beyond simple file encryption. Some employ double extortion tactics, where attackers encrypt data, exfiltrate sensitive information, and threaten to publish it publicly if the ransom is not paid. This puts pressure on victims, particularly organizations handling confidential customer data or proprietary business information. Ransomware development and propagation Understanding ransomware creation and distribution is essential for developing effective defense strategies. The ransomware lifecycle involves sophisticated development processes and diverse propagation methods that exploit technical vulnerabilities and human behavior. Ransomware development Ransomware is typically developed by cybercriminal organizations or individual threat actors with programming expertise. The creation process involves: Propagation methods Ransomware spreads through multiple attack vectors: Effects of a ransomware attack The impact of ransomware extends far beyond the immediate encryption of files. Organizations and individuals affected by ransomware experience multiple consequences that can have long-lasting repercussions on operations, finances, and reputation. Financial consequences Ransomware attacks inflict financial damage beyond file encryption. Victims may face ransom demands ranging from hundreds to millions of dollars, with no guarantee of data recovery even after payment. Additional expenses arise from incident response, forensic investigations, system restoration, and security enhancements, while regulatory non-compliance can lead to substantial legal fines and penalties for data breaches. Operational consequences Ransomware attacks cause significant operational disruption by crippling access to vital resources. Critical business data, customer information, and intellectual property may be lost or compromised, while essential services become unavailable, impacting customers, partners, and internal workflows. The resulting operational downtime often surpasses the ransom cost, as businesses can experience weeks or months of halted operations. Reputational damage Ransomware incidents often lead to lasting reputational damage as data breaches erode customer trust and confidence in an organization's ability to safeguard sensitive information. Public disclosure of such attacks can weaken market position, strain business relationships, and create a competitive disadvantage. Preventing ransomware attacks Preventing ransomware attacks requires a multi-layered defense strategy that combines technical controls, organizational policies, and user awareness. Understanding and implementing these protective measures reduces the risk of successful ransomware infections. Technical defenses Organizational practices What Wazuh offers for ransomware protection Wazuh is a free and open source security platform that provides comprehensive capabilities for detecting, preventing, and responding to ransomware threats. It is a unified XDR (Extended Detection and Response) and SIEM (Security Information and Event Management) platform. Wazuh helps organizations build resilience against ransomware attacks through its out-of-the-box capabilities and integration with other security platforms. Threat detection and prevention Wazuh employs multiple detection mechanisms to identify ransomware activities. These include: Incident response capabilities Use cases The following sections show some use cases of Wazuh detection and response to ransomware. Detecting and responding to DOGE Big Balls ransomware with Wazuh The DOGE Big Balls ransomware, a modified version of the FOG ransomware, combines technical exploits with psychological manipulation targeting enterprise environments. This malware variant delivers its payload through phishing campaigns or unpatched vulnerabilities. It then performs privilege escalation, reconnaissance, file encryption, and note creation on the victim's endpoint. Detection Wazuh detects the DOGE Big Balls ransomware using threat detection rules and a Wazuh Custom Database (CBD) list to match its specific pattern. These rules flag the execution of known reconnaissance commands and detect when multiple ransom notes appear across directories. These are DOGE Big Balls ransomware IOCs that indicate file encryption and other ransomware activities. Automated response Wazuh enables ransomware detection and removal using its File Integrity Monitoring (FIM) capability and integration with YARA. In this use case, Wazuh monitors the Downloads directory in real-time. When a new or modified file appears, it triggers the active response capability to execute a YARA scan. If a file matches known YARA ransomware signatures like DOGE Big Balls, the custom active response script deletes it automatically and logs the action. Custom decoders and rules on the Wazuh server parse those logs to generate alerts showing whether the file was detected and successfully removed. Detecting Gunra ransomware with Wazuh The Gunra ransomware is typically used by private cybercriminals to extort money from its victims. It utilizes a double-extortion model that encrypts files and exfiltrates data for publication should its victim fail to pay the ransom. The Gunra ransomware spreads through Windows systems by encrypting files, appending the .ENCRT extension, and leaving ransom notes named R3ADM3.txt. It deletes shadow copies, disables backup and antivirus services to block recovery, and uses Tor networks to hide its operators. These actions make data restoration difficult and help the attackers maintain anonymity during ransom negotiations. Detection The following Wazuh rules alert when ransom notes named R3ADM3.txt appear, system components like VSS or amsi.dll are tampered with, or suspicious modules such as urlmon.dll are loaded for network activity. The rules also track attempts to delete shadow copies or disable backup and admin functions, indicating behavior typical of ransomware preparing for file encryption. Automated response Wazuh performs automated responses to Gunra ransomware malicious file activities using its FIM capability and integration with VirusTotal. In this use case, the Wazuh File Integrity Monitoring (FIM) module monitors the Downloads folder in real-time, triggering scans whenever files are added or changed. A custom active response executable, then securely deletes any file that VirusTotal flags as a threat. Ransomware protection on Windows with Wazuh Wazuh provides ransomware protection and file recovery on monitored Windows endpoints using its command module and the Windows Volume Shadow Copy Service (VSS). This integration allows administrators to automatically take snapshots of monitored endpoints to recover files to a state before they are encrypted by malware. The following image shows successful Wazuh Active Response file recovery alerts. Conclusion Ransomware attacks pose significant financial, operational, and reputational damage. They require multi-layered defenses that combine early detection with incident response. Organizations that invest in these practices are better equipped to withstand and recover from such attacks. Wazuh provides capabilities that enable early detection and rapid response to contain ransomware attacks. It offers out-of-the-box capabilities for vulnerability detection, file integrity monitoring, log data analysis, and automated responses to prevent ransomware-caused data loss and downtime.