Cryptredol
Table of Contents
Overview
Ransomware:Win32/Cryptredol is a destructive malware strain with a dual-impact payload: it functions primarily as ransomware, encrypting victim data (`T1486`), but often includes a secondary cryptomining component (`T1496`) designed to monetize the system's hardware resources while the victim decides whether to pay the ransom. This dual-pronged attack maximizes the attacker's return on investment.
Understanding Cryptredol (Ransom-Miner)
To an end-user, the infection is catastrophic. Files become inaccessible, appended with a random extension, and the computer's fans spin loudly as the hidden miner consumes all available CPU power. For an organization, it requires immediate network isolation to prevent the rapid lateral spread of the encryption routine.
Execution and Dual-Payload Mechanics
Cryptredol is typically delivered via exploit kits or weaponized RDP access. Upon execution, it first disables Volume Shadow Copies (`vssadmin.exe delete shadows`) (`T1490`) to prevent easy data recovery. It then drops a secondary payload (often a variant of XMRig) to begin mining Monero (`T1496`) in the background. Simultaneously, it rapidly traverses local drives and mapped network shares, utilizing strong algorithms like AES or RSA to encrypt files (`T1486`). A ransom note is dropped in every affected directory.
Indicators of Compromise & Impact
The impact is total loss of data availability combined with severe system resource degradation. Host-based IoCs include the sudden renaming of thousands of files, the presence of ransom notes, EDR alerts for rapid file modification operations, and persistent 100% CPU utilization by unknown processes. System logs will show the execution of commands designed to inhibit system recovery. Network IoCs include connections to cryptocurrency mining pools (Stratum protocol) and a brief burst of traffic to a C2 server to transmit the victim's unique encryption ID.
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-RQA | Registry Query Auditing | Detect | T1012 | Audit mass registry queries targeted at security posture, installed software, and system configuration hives. |
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-PEA | Processor Execution Auditing | Detect | T1496 | Alert on sustained high CPU/GPU utilization by processes originating from temporary user directories and block stratum mining pool ports. |
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_CRYPTREDOL_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Cryptredol"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "cryptredol" 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 - Cryptredol (Ransomware) Execution & Triage
id: d295a1e2-de0e-5755-9278-df89c595ebe4
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Cryptredol 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/cryptredol
- 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.t1496
- attack.t1012
- attack.t1486
- attack.t1490
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_CRYPTREDOL_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Cryptredol 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 = "cryptredol" 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.
- Isolate the infected machine from the network immediately—pull the ethernet cable or disable the Wi-Fi adapter to stop the encryption from spreading to network shares.
- Do not immediately reboot the machine; if the encryption process is active, rebooting may finalize the damage or destroy volatile memory keys.
- Identify the initial infection vector (e.g., exposed RDP) to prevent further compromise.
- Restore operations from known-good, offline backups; paying the ransom is highly discouraged as it funds criminal enterprises.
What to Avoid
Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.
- Do not connect backup drives to the infected machine until it has been completely wiped and reimaged, as the ransomware will encrypt the backups.
- Avoid assuming the threat is just a miner based on CPU usage; always check for encrypted files and dropped ransom notes.
References & External Analysis
- Search "cryptredol" on VirusTotal (External Analysis)
- Search "cryptredol" on Any.Run (Sandbox Sandbox)
- Search "cryptredol" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Cryptredol and what threat category does it belong to?
Cryptredol 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 Cryptredol establish persistence and evade defensive controls?
Cryptredol 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 Cryptredol compromise?
Security teams responding to Cryptredol 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 Cryptredol employ during execution?
Cryptredol 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 Cryptredol, and what is the recommended recovery procedure?
Decryption availability for Cryptredol 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 Cryptredol from Windows?
Manual removal of Cryptredol 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.
What are the main symptoms of a Cryptredol infection?
Symptoms of Cryptredol 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 Cryptredol 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
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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.