Vbcryptor
Table of Contents
Overview
Ransomware:Win32/Vbcryptor is a broad detection name applied to various strains of ransomware, file encoders, and malicious crypters that are compiled using Microsoft Visual Basic (VB) or Visual Basic .NET (VB.NET). Because VB executables are often heavily dependent on the .NET framework and are relatively easy to decompile, malware authors use 'Vbcryptor' wrapper tools to heavily obfuscate their actual payloads, making static analysis extremely difficult.
Understanding Vbcryptor (Visual Basic Crypters)
To an end-user, an encounter with Vbcryptor usually ends in tragedy: personal files are suddenly appended with strange extensions (like `.locked` or `.crypto`), and a ransom note demands cryptocurrency to restore access. For a malware analyst, encountering a Vbcryptor file means the first step is unpacking. The outer VB layer is rarely the actual ransomware; instead, it is a highly obfuscated 'packer' or 'crypter' designed solely to evade antivirus (`T1027.002`). The true payload (which could be anything from a banking trojan to a well-known ransomware family like Locky or Cerber) is hidden inside, encrypted.
Execution and Unpacking Mechanics
Vbcryptor variants are distributed via phishing (`T1566.001`), drive-by downloads, or RDP brute-forcing. Upon execution (`T1204.002`), the VB executable loads into memory. It then executes a decryption routine to unpack its hidden payload directly into a hollowed-out process (Process Hollowing - `T1055.012`) like `svchost.exe` or `vbc.exe`. By running the payload exclusively in memory, the malware avoids dropping the true ransomware binary to the disk, bypassing many legacy, signature-based AV scanners. Once the hidden ransomware executes, it begins iterating through local and network drives (`T1083`), encrypting user files (`T1486`).
Indicators of Compromise & Impact
The impact is catastrophic data loss or severe operational downtime. Host-based IoCs include anomalous child processes spawning from generic Windows executables, mass file modifications (`T1486`), and the dropping of ransom notes (e.g., `DECRYPT_FILES.txt`). Network IoCs may include the payload attempting to communicate with Tor gateways or known C2 infrastructure.
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 (Ransomware payload) | Impact | ATT&CK ↗ |
T1027.002 | Obfuscated Files or Information: Software Packing (VB Crypters) | Defense Evasion | ATT&CK ↗ |
T1055.012 | Process Injection: Process Hollowing | Defense Evasion | ATT&CK ↗ |
T1083 | File and Directory Discovery | Discovery | 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-EDA | Executable Deobfuscation Analysis | Detect | T1027.002 | Deploy static entropy scanners and dynamic memory-unpacking heuristics to identify obfuscated and packed PE structures. |
D3-PHA | Process Hollowing Analysis | Detect | T1055.012 | Inspect unbacked executable memory regions (PAGE_EXECUTE_READWRITE) for replaced PE image headers inside legitimate host processes. |
D3-FDA | File Directory Access Auditing | Detect | T1083 | Audit and alert on high-frequency recursive directory queries executed by non-system and unclassified binaries. |
D3-FAED | File Alteration Early Detection | Detect | T1486 | Deploy canary files and monitor mass rename/encryption I/O spikes to terminate ransomware threads immediately. |
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_VBCRYPTOR_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Vbcryptor"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "vbcryptor" 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 - Vbcryptor (Ransomware) Execution & Triage
id: bd43bfc3-27be-5820-a1e7-cfbb32ae6d89
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Vbcryptor 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/vbcryptor
- 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.t1055_012
- attack.t1486
- attack.t1027_002
- attack.t1083
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_VBCRYPTOR_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Vbcryptor 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 = "vbcryptor" 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 disconnect the infected endpoint from the network (unplug ethernet, disable Wi-Fi) to stop the ransomware from encrypting shared network drives.
- Do not immediately reboot the machine; if the ransomware is currently executing, a reboot might destroy the encryption keys temporarily held in RAM.
- Capture a full memory dump; analysts can often extract the unpacked payload and sometimes the encryption keys directly from the hollowed process.
- Restore affected files from an offline, verified backup solution.
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; paying funds criminal organizations and there is no guarantee the decryptor provided will actually work.
- Avoid relying on static AV scans of the original Vbcryptor file; the outer VB shell is often highly polymorphic and changes its hash constantly.
References & External Analysis
- Search "vbcryptor" on VirusTotal (External Analysis)
- Search "vbcryptor" on Any.Run (Sandbox Sandbox)
- Search "vbcryptor" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Vbcryptor and what threat category does it belong to?
Vbcryptor 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 Vbcryptor establish persistence and evade defensive controls?
Vbcryptor 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 Vbcryptor compromise?
Security teams responding to Vbcryptor 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 Vbcryptor employ during execution?
Vbcryptor 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 Vbcryptor, and what is the recommended recovery procedure?
Decryption availability for Vbcryptor 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 Vbcryptor Ransomware from Windows?
Manual removal of Vbcryptor 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 Vbcryptor a virus or a Ransomware?
Vbcryptor is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Vbcryptor typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Vbcryptor infection?
Symptoms of Vbcryptor 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 Vbcryptor 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.