{ "family": "zepto", "sample_count": 1, "category": "ransomware", "description": "

Executive Summary

\nZepto is a highly destructive ransomware variant that gained massive notoriety in mid-2016. It is a direct evolution (and effectively a rebranded version) of the infamous Locky ransomware family. Zepto utilizes military-grade encryption to lock a victim's critical data, appends the `.zepto` extension to affected files, and demands a cryptocurrency ransom, causing immediate and catastrophic operational downtime.\n\n

Infection Vector and Technical Capabilities

\nZepto was primarily distributed through massive, automated spam campaigns orchestrated by the Necurs botnet. The phishing emails typically contained malicious `.zip` archives housing weaponized JavaScript (`.js`) or Visual Basic Script (`.vbs`) files, or `.docm` files with malicious macros.\n\nOnce the script is executed, Zepto operates with devastating efficiency:\n\n\n

Threat Assessment

\nA Zepto infection is a catastrophic security incident resulting in massive data loss. Due to the strength of the RSA/AES hybrid encryption, files cannot be recovered without the private key held by the attackers or a viable offline backup.\n\n

Incident Response and Remediation

\n", "cta": "Published by the SystemHelpdesk team.", "aliases": [ "Ransomware.Zepto", "Trojan-Ransom.Win32.Locky.Zepto", "Filecoder.Zepto" ], "enrichment_level": "expert-seo", "faq": [ { "@type": "Question", "name": "What is Zepto and what threat category does it belong to?", "acceptedAnswer": { "@type": "Answer", "text": "Zepto is classified as a Ransomware. Documented across security telemetry, it is engineered to execute unauthorized operations, establish persistent footholds on target endpoints, and facilitate malicious campaigns targeting enterprise and individual environments." } }, { "@type": "Question", "name": "How does Zepto establish persistence and evade defensive controls?", "acceptedAnswer": { "@type": "Answer", "text": "Zepto typically establishes persistence through registry run keys, scheduled tasks, or service installations, while evading signature-based antivirus solutions through code obfuscation, memory injection, or anti-analysis sandbox checks." } }, { "@type": "Question", "name": "What are the essential incident response steps for mitigating a Zepto compromise?", "acceptedAnswer": { "@type": "Answer", "text": "Security teams responding to Zepto should immediately isolate affected endpoints from the network, perform memory triage to capture volatile forensic artifacts, audit registry and startup persistence mechanisms, revoke exposed user credentials, and restore systems from verified, clean backups." } }, { "@type": "Question", "name": "What cryptographic algorithms and file targeting techniques does Ransomware.Zepto employ during execution?", "acceptedAnswer": { "@type": "Answer", "text": "Ransomware.Zepto typically leverages hybrid cryptographic architectures combining symmetric stream or block ciphers (such as AES-256 or ChaCha20) for rapid file encryption with asymmetric algorithms (such as RSA-2048 or Curve25519) to securely protect the session keys. It aggressively targets sensitive file extensions including corporate documents, databases, virtual disks, and backups while systematically executing commands to delete Volume Shadow Copies (vssadmin delete shadows /all /quiet) and disable system recovery options." } }, { "@type": "Question", "name": "Are decryptors available for Ransomware.Zepto, and what is the recommended recovery procedure?", "acceptedAnswer": { "@type": "Answer", "text": "Decryption availability for Ransomware.Zepto depends on whether security researchers or law enforcement (such as the No More Ransom initiative) have recovered the master private keys or discovered flaws in its key generation routines. Victims should never pay the extortion demand, as payment fuels criminal operations without guaranteeing file restoration. The recommended recovery procedure entails isolating infected hosts, conducting forensic disk imaging, identifying the root access vector, and restoring validated systems from immutable offline backups." } } ], "faq_count": 5, "mitre_attack": [ "T1486", "T1490", "T1566.001", "T1059.005", "T1568.002" ], "cisa_advisory": null, "last_updated": "2026-10-15", "type": "Ransomware", "target_industries": [ "Healthcare", "Critical Infrastructure", "Enterprise" ], "motivation": "Financial Extortion", "threat_actors": [ "Unknown / Cybercriminal" ], "target_geographies": [ "Global" ], "attack_stage": [ "defense_evasion", "impact" ], "ecosystem": [ "windows_pe" ], "is_emerging": false, "mitre_attack_detail": [ { "id": "T1486", "name": "Data Encrypted for Impact", "tactic": "Impact" }, { "id": "T1490", "name": "Inhibit System Recovery (Behaviorally blocking the deletion of backups)", "tactic": "Impact" }, { "id": "T1566.001", "name": "Phishing: Spearphishing Attachment", "tactic": "Initial Access" }, { "id": "T1059.005", "name": "Command and Scripting Interpreter: Visual Basic (VBScript within the ASP file)", "tactic": "Execution" }, { "id": "T1568.002", "name": "Dynamic Resolution: Domain Generation Algorithms (DGA) (Evading C2 blacklisting)", "tactic": "Command and Control" } ], "containment_steps": [ "Immediately isolate affected host(s) from the internal network (disconnect physical Ethernet and disable Wi-Fi/Bluetooth) to prevent Zepto from spreading laterally or encrypting network-attached storage (NAS) and shared SMB volumes.", "Preserve volatile system memory (RAM capture) on a representative endpoint before attempting a reboot or power-down, as Zepto symmetric encryption keys or uncompiled payload components may still reside in memory.", "Audit process execution logs and terminate active scripting interpreters (e.g. PowerShell, CMD, WScript) or commands executing 'vssadmin.exe delete shadows' or 'wbadmin' used by Zepto to inhibit recovery.", "Investigate the initial compromise vector (such as exposed RDP instances, spearphishing attachments, or vulnerable edge gateways) and enforce an immediate credential reset for all compromised Active Directory accounts.", "Restore critical assets and databases exclusively from verified, air-gapped, or immutable offline backups once the Zepto binary and related persistence hooks are eradicated." ], "what_to_avoid": [ "Do not restart or power cycle infected systems prematurely; doing so destroys volatile RAM encryption keys and may trigger bootloader locking logic embedded in Zepto.", "Avoid negotiating or paying the extortion demand without prior forensic evaluation and consultation with incident response specialists, as payment does not guarantee data recovery.", "Do not connect clean backup drives or external storage to the affected network until Zepto eradication is completely verified." ], "target_platforms": [ "Windows 11", "Windows 10", "Windows Server 2022", "Windows Server 2019" ] }