Rasftuby
Table of Contents
Overview
Rasftuby (identified across antivirus telemetries and threat intelligence feeds under signatures including Ransom:Win32/Rasftuby, Trojan-Ransom.Win32.Rasftuby, and Trojan.Rasftuby) is a destructive crypto-ransomware and extortion threat active since 2016. Delivered predominantly through malicious spam campaigns with macro-laced documents and drive-by download compromise chains, Rasftuby executes immediate evasion and reconnaissance routines upon system infiltration. Rasftuby terminates database, backup, and endpoint security processes to release open file handles before traversing local storage drives, removable media, and mounted network file shares. Using AES-256 symmetric encryption combined with RSA public-key protection, Rasftuby encrypts documents, spreadsheets, databases, and archives, appending an extortion extension to affected files. It deletes Volume Shadow Copies (vssadmin delete shadows /all /quiet), alters desktop background settings to display extortion notices, and demands cryptocurrency ransoms in exchange for a proprietary decryptor.
Known aliases
Threat reports may refer to this family under multiple names:
Family Pedigree & Lineage
Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:
Known Derivatives & Downstream Variants: Ransom:Win32/Rasftuby.A · Ransom:Win32/Rasftuby.B
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1486 · T1490 · T1547.001 · T1082 · T1071.001
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.
MITRE D3FEND™ Defensive Countermeasures
Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):
| D3FEND ID | Countermeasure Name | Tactic | Countered ATT&CK | Defensive Guidance |
|---|---|---|---|---|
D3-WAF | Web Content Filtering & Inspection | Filter | T1071.001 | Block newly registered domains (NRDs) and inspect HTTP Host and URI headers for known C2 profiles. |
D3-SDA | System Discovery Analysis | Detect | T1082 | Alert on rapid enumerations of systeminfo, hostname, and registry hardware trees in short intervals. |
D3-FAED | File Alteration Early Detection | Detect | T1486 | Deploy canary files and monitor mass rename/encryption I/O spikes to terminate ransomware threads immediately. |
D3-VSS | Volume Shadow & Snapshot Hardening | Harden | T1490 | Block execution of vssadmin.exe and wmic shadowcopy delete; maintain air-gapped immutable backup repositories. |
D3-RPM | Registry Persistence Monitoring | Detect | T1547.001 | Audit and restrict write privileges to user and machine-level Registry Run/RunOnce keys using Endpoint Privilege Management. |
Tiered Detection Rules (Cisco CAIRN Model)
Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:
Tier 1 Primitive Artifact Rule (Fast Triage)
Matches raw strings and file markers. Vulnerable to binary repacking and simple obfuscation.
rule MALWARE_WIN_RASFTUBY_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Rasftuby"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "rasftuby" ascii wide nocase
$s2 = "ransom:win32/rasftuby" ascii wide nocase
$s3 = "trojan-ransom.win32.rasftuby" ascii wide nocase
$s4 = "trojan.rasftuby" ascii wide nocase
$s5 = "win32/rasftuby" ascii wide nocase
$s6 = "ransom:win32/rasftuby.a" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Tier 2 Behavioral Context Rule (Process Chains & Sigma)
Tracks parent-child process anomalies and suspicious scripting telemetry. Resilient against file renames.
title: SystemHelpDesk Detection - Rasftuby (Ransomware) Execution & Triage
id: fea64295-39a0-53c4-a9c0-52838678dde4
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Rasftuby malware family. Detects volume shadow copy deletion, boot status
tampering, and recovery inhibition characteristic of modern ransomware operations.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/rasftuby
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.ransomware
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1486
- attack.t1490
- attack.t1547_001
- attack.t1082
- attack.t1071_001
logsource:
category: process_creation
product: windows
detection:
selection_process:
Image|endswith:
- \vssadmin.exe
- \wmic.exe
- \wbadmin.exe
- \bcdedit.exe
CommandLine|contains:
- delete shadows
- shadowcopy delete
- resize shadowstorage
- recoveryenabled no
- ignoreallfailures
condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: criticalTier 3 Attribution Fingerprint Rule (High Fidelity)
Deep signature matching distinctive operational fingerprints and payload characteristics.
rule MALWARE_WIN_RASFTUBY_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Rasftuby tradecraft"
tier = "T3 - Attribution Fingerprint"
confidence = "High (Confirmed Family Signature)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
// Core family identifier & heuristic payload signatures
$attrib_str = "rasftuby" ascii wide nocase
$pe_magic = "MZ" ascii
$net_marker = "http" ascii nocase
condition:
uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}References & External Analysis
- Microsoft Defender Threat Encyclopedia - Ransom:Win32/Rasftuby
- Trend Micro Threat Encyclopedia - Ransom.Win32.Rasftuby
- Search "rasftuby" on VirusTotal (External Analysis)
- Search "rasftuby" on Any.Run (Sandbox Sandbox)
- Search "rasftuby" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Ransom:Win32/Rasftuby?
Rasftuby is a destructive ransomware threat that encrypts user data with AES-256 and displays extortion demands for cryptocurrency payment.
How does Rasftuby prevent victims from recovering data?
It executes vssadmin to delete all Volume Shadow Copies and disables Windows automated startup recovery via bcdedit.
What files are targeted by Rasftuby for encryption?
It targets documents, spreadsheets, databases, financial records, archives, and multimedia files on local and network drives.
How is Rasftuby distributed to enterprise systems?
It spreads via phishing emails with malicious document attachments, compromised software downloads, and exploit kit drive-by infections.
What defensive measures protect against Rasftuby ransomware?
Maintain offline immutable backups, enable Controlled Folder Access in Microsoft Defender, and restrict execution of unauthorized scripts.
How do I remove the Rasftuby Ransomware from Windows?
Manual removal of Rasftuby 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 Rasftuby a virus or a Ransomware?
Rasftuby is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Rasftuby typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Rasftuby infection?
Symptoms of Rasftuby 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.
Protect Your Network Against Ransomwares
Want to prevent Rasftuby and similar threats from compromising your organization? Read our comprehensive defensive guide: Ransomware Containment & Incident Response.
📣 Threat Intel Correction or Update?
Notice an outdated IOC, unlisted alias, or disputed attribution? Threat researchers are invited to propose an update on GitHub or contact the SystemHelpDesk research desk. All community revisions are credited in our public CHANGELOG.
Machine-readable
Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/rasftuby.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.