Ranserkd
Table of Contents
Overview
Ransom:Win32/Ranserkd is a highly destructive ransomware variant designed to systematically encrypt all valuable data on an infected endpoint or network share, followed by an extortion demand. It utilizes strong cryptographic algorithms (typically AES combined with RSA) to ensure that recovering the locked files is mathematically impossible without paying the attackers for the unique private decryption key.
Understanding the Ranserkd Threat
To a victim, a Ranserkd infection represents a catastrophic loss of data; documents, databases, and photos become inaccessible, appended with a strange file extension, and a ransom note appears on the desktop. For an enterprise, it triggers a critical incident response involving total network isolation to prevent the ransomware from spreading to critical servers and backups.
Execution and Encryption Mechanics
Ranserkd is frequently deployed manually by attackers after they have already breached the network (e.g., via compromised RDP credentials or an Initial Access Broker) (`T1078`), or delivered via massive malspam campaigns (`T1566.001`). Upon execution, the ransomware first attempts to neutralize endpoint defenses and delete Windows Volume Shadow Copies (`vssadmin.exe delete shadows`) to prevent easy data restoration (`T1490`). It then aggressively scans all local drives and mapped network shares, rapidly encrypting files that match a hardcoded list of valuable extensions (e.g., `.docx`, `.sql`, `.pdf`) (`T1486`). Finally, it drops a ransom note (often a `.txt` or `.html` file) detailing payment instructions via cryptocurrency.
Indicators of Compromise & Impact
The impact is total data denial of service. Host-based IoCs include massive spikes in CPU and disk I/O activity caused by the rapid encryption process. EDR systems will flag the execution of `vssadmin.exe` or `bcdedit.exe` attempting to disable recovery features. Files across the system will suddenly change extensions, and the ransomware executable itself may be found running from the `%Temp%` or `%AppData%` directories.
MITRE ATT&CK Techniques
Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:
| Technique | Name | Tactic | Official Spec |
|---|---|---|---|
T1486 | Data Encrypted for Impact | Impact | ATT&CK ↗ |
T1490 | Inhibit System Recovery (Deleting Shadow Copies) | Impact | ATT&CK ↗ |
T1078 | Valid Accounts (Common deployment method for enterprise ransomware) | Initial Access | ATT&CK ↗ |
T1485 | Data Destruction (If encryption is flawed or keys are lost) | Impact | ATT&CK ↗ |
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-MFA | Multi-factor Authentication | Harden | T1078 | Enforce mandatory phishing-resistant FIDO2 multi-factor authentication across all external access portals. |
D3-WORM | Immutable Backup Storage | Harden | T1485 | Store primary backups in Write-Once-Read-Many (WORM) cloud repositories protected by multi-party out-of-band credentials. |
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. |
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_RANSERKD_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Ranserkd"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "ranserkd" 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 - Ranserkd (Ransomware) Execution & Triage
id: 8753ccfa-b172-5eec-b7b8-f7557dc17bb0
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Ranserkd 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/ranserkd
- 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.t1485
- attack.t1490
- attack.t1078
- attack.t1486
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_RANSERKD_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Ranserkd 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 = "ranserkd" 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.
- Immediately sever the infected endpoint from the network (physically pull the Ethernet cable or disable the switch port) to stop it from encrypting mapped network drives.
- Do NOT reboot the infected machine; capture a live memory image (RAM dump), as the encryption keys might temporarily reside in memory.
- Identify the exact Ranserkd variant and consult resources like 'No More Ransom' to see if a known decryption flaw exists before considering payment.
- Restore the encrypted systems from secure, offline backups that were isolated from the network at the time of the attack.
What to Avoid
Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.
- Do not pay the ransom immediately; paying funds criminal syndicates and there is no guarantee the provided decryptor will actually work.
- Avoid reconnecting restored machines to the network until the initial entry vector (e.g., a vulnerable VPN or weak RDP password) has been completely secured.
References & External Analysis
- Search "ranserkd" on VirusTotal (External Analysis)
- Search "ranserkd" on Any.Run (Sandbox Sandbox)
- Search "ranserkd" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Ranserkd and what threat category does it belong to?
Ranserkd 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 Ranserkd establish persistence and evade defensive controls?
Ranserkd 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 Ranserkd compromise?
Security teams responding to Ranserkd 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 Ranserkd employ during execution?
Ranserkd 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 Ranserkd, and what is the recommended recovery procedure?
Decryption availability for Ranserkd 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 Ranserkd Ransomware from Windows?
Manual removal of Ranserkd 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 Ranserkd a virus or a Ransomware?
Ranserkd is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Ranserkd typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Ranserkd infection?
Symptoms of Ranserkd 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 Ranserkd 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.