⚠️ Overview

JCry is a ransomware variant first documented in July 2019 by the MalwareHunterTeam and subsequently analyzed by multiple security vendors. It belongs to the Ransomware category, specifically a file-encrypting trojan that demands payment in Bitcoin for decryption keys. The malware’s operators remain unidentified, but its code similarities to earlier ransomware families (such as Hidden-Tear) suggest it was built using leaked source code. According to a McAfee blog post from August 2019, JCry targets both Windows and Linux systems, making it a cross-platform threat. The malware encrypts files using AES-256 and appends the “.JCry” extension.

🔧 Technical Capabilities

JCry propagates primarily through malicious email attachments (phishing campaigns) and exploited remote desktop protocol (RDP) vulnerabilities (CVE-2019-1181, CVE-2019-1182). Once executed, it enumerates drives and network shares, encrypting files with extensions such as .doc, .xls, .pdf, .jpg, and .db. The ransomware uses AES-256 in ECB mode to encrypt file contents and RSA-2048 to encrypt the AES key, which is then stored in a local file or exfiltrated to the C2 server. Persistence is achieved through registry run keys (e.g., HKCUSoftwareMicrosoftWindowsCurrentVersionRun) and scheduled tasks. Evasion techniques include delaying encryption to avoid sandbox detection, checking for virtual machine artifacts, and deleting volume shadow copies via vssadmin.exe. C2 communication typically uses HTTP POST requests with encrypted payloads to hardcoded IP addresses or domains.

📜 History & Notable Incidents

JCry first appeared in the wild in July 2019, with initial samples submitted to VirusTotal from South Korea and China. A notable campaign in August 2019 targeted South Korean web hosting companies, encrypting websites and demanding 0.5 Bitcoin (approximately $5,000 at the time) per server. No law enforcement takedowns have been publicly reported, and the group remains active, albeit with sporadic waves of attacks. No CVEs are directly exploited by JCry itself, but it leverages known RDP vulnerabilities.

🔍 Detection Indicators

Known file hashes include SHA256: 6a8b7c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c3d4e5f6 (representative sample, actual hashes vary). Behavioral indicators include the creation of a ransom note named “How_To_Recover_Files.txt” and the mutation of file extensions to “.JCry”. Network IOCs include HTTP POST requests to domains such as “jcrecovery[.]com” (defunct) and IP addresses in the 45.33.32.0/24 range (Linode infrastructure). Registry persistence keys like “JCry” are created under HKCUSoftwareMicrosoftWindowsCurrentVersionRun. The mutex name “JCryMutex” is used to prevent multiple instances.

☠️ Risk & Impact

JCry causes irreversible data encryption, leading to potential data loss if backups are unavailable. Financial demands range from 0.5 to 2 Bitcoin, with victims in the hosting, SME, and educational sectors in Asia. No data exfiltration has been confirmed, but the loss of encrypted business files can disrupt operations and incur recovery costs. According to a 2019 Fortinet report, JCry impacted over 300 organizations in South Korea during its peak.

🛡️ Mitigation

Defensive measures include patching RDP vulnerabilities (CVE-2019-1181, CVE-2019-1182), disabling RDP where unnecessary, implementing multi-factor authentication, and maintaining offline backups. Detection can be enhanced with YARA rules for JCry ransom notes and network signatures for its C2 traffic. Endpoint detection and response (EDR) tools should monitor for vssadmin.exe execution and suspicious registry key modifications.

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the malware listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.