Snow
Overview
Executive Summary
Snow (often associated with the Snow Ransomware family or a specific Trojan downloader) is a malicious threat designed to infiltrate Windows systems, establish persistence, and execute destructive payloads. When operating as ransomware, Snow utilizes strong encryption algorithms to lock down the victim's critical data, demanding a ransom payment in exchange for the decryption key, causing immediate and severe operational downtime.Infection Vector and Technical Capabilities
Snow is predominantly distributed via targeted phishing campaigns containing weaponized attachments, or by exploiting weak Remote Desktop Protocol (RDP) credentials exposed to the public internet. Upon successful execution, the malware operates with a focus on speed and destruction:- Defense Evasion: Snow typically attempts to disable local Windows Defender services and terminate processes associated with enterprise backup solutions and database servers (e.g., SQL Server, Exchange) to ensure all data files are unlocked and ready for encryption.
- Rapid File Encryption: The ransomware scans local drives and mapped network shares, targeting specific file extensions (documents, databases, archives). It encrypts these files using a strong cryptographic algorithm (often AES/RSA hybrid) and appends a specific extension (like `.snow`) to the encrypted files.
- Shadow Copy Deletion: To prevent easy recovery, Snow almost universally executes commands (like `vssadmin.exe delete shadows /all /quiet`) to instantly destroy Windows Volume Shadow Copies and disable local backup routines.
- Extortion: After the encryption phase is complete, it drops a ransom note outlining the payment instructions (usually in cryptocurrency) and threatening permanent data loss.
Threat Assessment
A Snow ransomware infection is a catastrophic security incident resulting in immediate, severe operational downtime and massive data loss. Due to the strength of modern encryption, files cannot be recovered without the private key 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
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1059: 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_SNOW {
meta:
description = "Detects Snow (ransomware)"
author = "SystemHelpdesk Boilerplate Generator"
date = "2026-07-06"
strings:
$s1 = "snow" ascii wide nocase
$s2 = "ransomware.snow" ascii wide nocase
$s3 = "trojan-ransom.win32.snow" ascii wide nocase
$s4 = "filecoder.snow" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Sigma Rule
title: Suspicious Snow Activity
id: 2b93fbdf27d43547bec8794054c28e00
status: experimental
description: Detects generic indicators of the snow malware family.
logsource:
category: process_creation
product: windows
detection:
selection:
Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
CommandLine|contains:
- "*snow*"
- "*ransomware.snow*"
- "*trojan-ransom.win32.snow*"
- "*filecoder.snow*"
condition: selection
level: mediumReferences & External Analysis
- Search "snow" on VirusTotal (External Analysis)
Frequently Asked Questions
How do I remove the Snow Ransomware from Windows?
Manual removal of Snow 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 Snow a virus or a Ransomware?
Snow is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Snow typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Snow infection?
Symptoms of Snow 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 Snow 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/snow.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.