Urausy
Table of Contents
Overview
Ransom:Win32/Urausy (also known as a 'Police Trojan') represents a massive, historical wave of screen-locking ransomware. Unlike modern crypto-ransomware that encrypts files, Urausy locks the user's desktop interface entirely (`T1486`) and displays a localized, highly realistic warning purportedly from a local law enforcement agency (like the FBI, Interpol, or local police). The warning claims the user was caught viewing illegal content and must pay a 'fine' (usually via pre-paid cards like Ukash or Paysafecard) to unlock the machine.
Understanding Urausy (Screen-Locking Ransomware)
To an end-user, the computer is completely unusable; upon boot, they are immediately presented with a full-screen police warning that cannot be closed. For a SOC analyst, Urausy is a legacy threat that highlights the evolution of ransomware from psychological extortion (scareware) to actual cryptographic damage.
Execution and Extortion Mechanics
Urausy was primarily distributed via exploit kits (like Blackhole or Fiesta) (`T1189`) injected into compromised websites. Upon successful exploitation, the payload is dropped and executes. It achieves persistence by replacing the default Windows shell (typically `explorer.exe`) in the registry (`HKCU\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell`) with its own executable (`T1547.004`). It actively monitors for and terminates task manager processes (`taskmgr.exe`) to prevent the user from killing the locker (`T1562.001`). Crucially, Urausy uses geolocation (via the victim's IP address) to display a customized ransom note in the correct language, featuring the logos of local law enforcement.
Indicators of Compromise & Impact
The impact is a total denial of access to the desktop environment, though the underlying files are *not* encrypted. Host-based IoCs include the modification of the Winlogon Shell registry key, the presence of the malicious executable in the `%AppData%` directory, and the inability to launch `taskmgr.exe`. Network IoCs involve initial connections to known exploit kit landing pages.
MITRE ATT&CK Techniques
Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:
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-FAED | File Alteration Early Detection | Detect | T1486 | Deploy canary files and monitor mass rename/encryption I/O spikes to terminate ransomware threads immediately. |
D3-RPM | Registry Persistence Monitoring | Detect | T1547.004 | Monitor changes to standard autostart run keys (HKLM\Software\Microsoft\Windows\CurrentVersion\Run) and Startup folders. |
D3-STA | Security Tool Anti-Tamper Enforcement | Harden | T1562.001 | Block unauthorized modification of antivirus registry flags and prevent stopping security agent services. |
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_URAUSY_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Urausy"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "urausy" 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 - Urausy (Ransomware) Execution & Triage
id: dd3dfedf-6d7f-5516-9b9d-0b098281c578
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Urausy 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/urausy
- 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.t1547_004
- attack.t1562_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_URAUSY_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Urausy 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 = "urausy" 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
}Containment & Response Steps
Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.
- Boot the infected machine into Safe Mode with Command Prompt; this often bypasses the Winlogon Shell hijack.
- From the command prompt, launch `regedit.exe` and restore the `HKCU\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell` key back to `explorer.exe`.
- Locate and delete the malicious Urausy executable (often located in `%AppData%` or `%Temp%`).
- After rebooting normally, run a full AV scan to remove any secondary droppers that arrived with the exploit kit.
What to Avoid
Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.
- Do not format the drive or restore from backup immediately; unlike crypto-ransomware, Urausy infections can usually be removed without any data loss.
- Avoid paying the 'fine'; it goes directly to cybercriminals, not law enforcement.
References & External Analysis
- Search "urausy" on VirusTotal (External Analysis)
- Search "urausy" on Any.Run (Sandbox Sandbox)
- Search "urausy" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Urausy and what threat category does it belong to?
Urausy 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.
How does Urausy establish persistence and evade defensive controls?
Urausy 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.
What are the essential incident response steps for mitigating a Urausy compromise?
Security teams responding to Urausy 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.
What cryptographic algorithms and file targeting techniques does Urausy employ during execution?
Urausy 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.
Are decryptors available for Urausy, and what is the recommended recovery procedure?
Decryption availability for Urausy 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.
How do I remove the Urausy Ransomware from Windows?
Manual removal of Urausy 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 Urausy a virus or a Ransomware?
Urausy is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Urausy typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Urausy infection?
Symptoms of Urausy 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 Urausy 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.
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Ecosystem & Interactive Environments
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