Zepto
Overview
Executive Summary
Zepto 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.Infection Vector and Technical Capabilities
Zepto 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. Once the script is executed, Zepto operates with devastating efficiency:- Evasion and C2 Communication: The malware often uses a Domain Generation Algorithm (DGA) to rapidly locate its command-and-control servers. It securely negotiates and receives the public RSA key required to begin the encryption process.
- Rapid File Encryption: Zepto scans local drives, removable media, and specifically targets all mapped and unmapped network shares. It encrypts files using a hybrid RSA-2048 and AES-128 algorithm, replacing the original filename and appending the `.zepto` extension.
- Shadow Copy Deletion: To prevent easy recovery, Zepto executes commands (such as `vssadmin.exe delete shadows /all /quiet`) to instantly destroy Windows Volume Shadow Copies and disable local backup routines.
- Extortion: After encryption, it drops a ransom note (often `_HELP_instructions.html` and `.bmp` files) in every affected directory and changes the desktop wallpaper to display the payment demands.
Threat Assessment
A 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.Incident Response and Remediation
- Immediate Physical Isolation: Disconnect the infected machine from the network immediately (pull the Ethernet cable/disable Wi-Fi) to halt the encryption process and prevent the ransomware from traversing SMB shares to encrypt centralized file servers.
- Do Not Reboot: Leave the machine powered on. Rebooting may trigger further destructive routines or destroy the encryption key if it temporarily resides in RAM.
- Restore from Offline Backups: The only reliable remediation is to completely wipe the infected system (bare-metal reinstall) and restore the data from secure, offline backups that were unreachable by the ransomware.
Known aliases
Threat reports may refer to this family under multiple names:
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1486 T1490 T1566.001 T1059.005 T1568.002
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1059.005: Restrict execution of scripting languages such as PowerShell, VBScript, or Python to authorized administrators. Enforce Script Block Logging.
- T1566.001: Scan email attachments for malicious macros, scripts, or suspicious archive files.
Generated Detections (Boilerplate)
These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.
YARA Rule
rule MALWARE_WIN_ZEPTO {
meta:
description = "Detects Zepto (ransomware)"
author = "SystemHelpdesk Boilerplate Generator"
date = "2026-07-06"
strings:
$s1 = "zepto" ascii wide nocase
$s2 = "ransomware.zepto" ascii wide nocase
$s3 = "trojan-ransom.win32.locky.zepto" ascii wide nocase
$s4 = "filecoder.zepto" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Sigma Rule
title: Suspicious Zepto Activity
id: 249183b8da02a920a07e546af1088ced
status: experimental
description: Detects generic indicators of the zepto malware family.
logsource:
category: process_creation
product: windows
detection:
selection:
Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
CommandLine|contains:
- "*zepto*"
- "*ransomware.zepto*"
- "*trojan-ransom.win32.locky.zepto*"
- "*filecoder.zepto*"
condition: selection
level: mediumReferences & External Analysis
- Search "zepto" on VirusTotal (External Analysis)
Frequently Asked Questions
How do I remove the Zepto Ransomware from Windows?
Manual removal of Zepto is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.
Is Zepto a virus or a Ransomware?
Zepto is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Zepto typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Zepto infection?
Symptoms of Zepto can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.
Related Families (Category: ransomware)
Explore other malware families in the same category:
Protect Your Network Against Ransomwares
Want to prevent Zepto and similar threats from compromising your organization? Read our comprehensive defensive guide: Ransomware Protection Guide.
Machine-readable
Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/zepto.json
Ecosystem & Interactive Environments
This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.