Cryptinject

Overview

Cryptinject (classified in antimalware definitions under designations including Ransom:Win32/Cryptinject, Trojan:Win32/Cryptinject, and VirTool:Win32/Cryptinject) is an evasive crypto-ransomware loader and injector. Rather than encrypting files from its own process space, Cryptinject specializes in process hollowing and memory injection into legitimate Windows binaries (such as svchost.exe, explorer.exe, or vssadmin.exe). From within the injected trusted process context, the ransomware payload evades standard behavioral heuristics while recursively encrypting local and network share files using AES-256 and demanding cryptocurrency payments.

Known aliases

Threat reports may refer to this family under multiple names:

• Ransom:Win32/Cryptinject
• Trojan:Win32/Cryptinject
• VirTool:Win32/Cryptinject
• Win32/Cryptinject
• Cryptinject Ransomware

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

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.
• T1566.001: Scan email attachments for malicious macros, scripts, or suspicious archive files.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

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:

rule MALWARE_WIN_CRYPTINJECT_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Cryptinject"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "cryptinject" ascii wide nocase
        $s2 = "ransom:win32/cryptinject" ascii wide nocase
        $s3 = "trojan:win32/cryptinject" ascii wide nocase
        $s4 = "virtool:win32/cryptinject" ascii wide nocase
        $s5 = "win32/cryptinject" ascii wide nocase
        $s6 = "cryptinject ransomware" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Cryptinject (Ransomware) Execution & Triage
id: 4b6ef230-8bb7-578e-9a9c-411d73f382e3
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Cryptinject 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/cryptinject
- 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.t1490
- attack.t1057
- 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: critical

rule MALWARE_WIN_CRYPTINJECT_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Cryptinject 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 = "cryptinject" 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.

1. Instantly isolate the endpoint; Cryptinject alerts are highly correlated with active Cobalt Strike beacons and imminent ransomware deployment.
2. Do NOT attempt to manually terminate the injected system process (e.g., `svchost.exe`), as this will likely crash the operating system.
3. Capture a full forensic memory image (RAM dump) immediately. This is critical for extracting the decrypted payload and identifying the C2 infrastructure.
4. Initiate a hunt across the network for lateral movement (e.g., unusual SMB traffic, Pass-the-Hash) originating from the infected host.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not assume the threat is mitigated if the initial loader file is quarantined; the injected payload is already running in memory.
2. Avoid relying solely on network blocklists; advanced injected payloads often use Domain Fronting or legitimate cloud services for C2.

References & External Analysis

• Microsoft Defender Security Intelligence - Ransom:Win32/Cryptinject
• Trend Micro Security Research - Ransom.Win32.Cryptinject
• MITRE ATT&CK - Process Injection: Process Hollowing (T1055.012)
• Search "cryptinject" on VirusTotal (External Analysis)
• Search "cryptinject" on Any.Run (Sandbox Sandbox)
• Search "cryptinject" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Cleanpcpro
• Magnat
• Mdeclass
• Phpain
• Sentinel
• Zxrloader
• Cobalt
• Silcon

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/cryptinject.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.