{
  "family": "cryptinject",
  "sample_count": 15,
  "category": "ransomware",
  "description": "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.",
  "cta": "Published by the SystemHelpdesk Threat Intelligence Team.",
  "aliases": [
    "Ransom:Win32/Cryptinject",
    "Trojan:Win32/Cryptinject",
    "VirTool:Win32/Cryptinject",
    "Win32/Cryptinject",
    "Cryptinject Ransomware"
  ],
  "enrichment_level": "curated_sourced",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Ransom:Win32/Cryptinject?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Cryptinject is a ransomware injector that hollows out legitimate Windows processes to encrypt files invisibly."
      }
    },
    {
      "@type": "Question",
      "name": "Why does Cryptinject inject into legitimate processes?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "By executing inside trusted system binaries like svchost.exe, it evades basic antivirus detection and behavioral heuristics."
      }
    },
    {
      "@type": "Question",
      "name": "What injection methods does Cryptinject use?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It uses process hollowing, thread hijacking, and manual PE mapping in target system process memory spaces."
      }
    },
    {
      "@type": "Question",
      "name": "How does Cryptinject encrypt system files?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "The injected code spawns worker threads that scan local and mapped drives, encrypting data with AES-256."
      }
    },
    {
      "@type": "Question",
      "name": "How can security defenders detect Cryptinject activity?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Deploy modern EDR solutions with memory inspection, process hollowing detection, and anomalous file I/O monitoring."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1055.012",
    "T1486",
    "T1490",
    "T1057",
    "T1083",
    "T1135"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-10-15",
  "mitre_attack_detail": [
    {
      "id": "T1055.001",
      "name": "Process Injection: Dynamic-link Library Injection",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1027.002",
      "name": "Obfuscated Files or Information: Software Packing",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1620",
      "name": "Reflective Code Loading",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1071.001",
      "name": "Application Layer Protocol: Web Protocols",
      "tactic": "Command and Control"
    },
    {
      "id": "T1566.001",
      "name": "Phishing: Spearphishing Attachment",
      "tactic": "Initial Access"
    }
  ],
  "containment_steps": [
    "Instantly isolate the endpoint; Cryptinject alerts are highly correlated with active Cobalt Strike beacons and imminent ransomware deployment.",
    "Do NOT attempt to manually terminate the injected system process (e.g., `svchost.exe`), as this will likely crash the operating system.",
    "Capture a full forensic memory image (RAM dump) immediately. This is critical for extracting the decrypted payload and identifying the C2 infrastructure.",
    "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": [
    "Do not assume the threat is mitigated if the initial loader file is quarantined; the injected payload is already running in memory.",
    "Avoid relying solely on network blocklists; advanced injected payloads often use Domain Fronting or legitimate cloud services for C2."
  ],
  "target_industries": [
    "Healthcare",
    "Critical Infrastructure",
    "Enterprise"
  ],
  "motivation": "Financial Extortion",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "defense_evasion",
    "impact"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "sources": [
    {
      "name": "Microsoft Defender Security Intelligence - Ransom:Win32/Cryptinject",
      "url": "https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Ransom:Win32/Cryptinject"
    },
    {
      "name": "Trend Micro Security Research - Ransom.Win32.Cryptinject",
      "url": "https://www.trendmicro.com/vinfo/us/threat-encyclopedia/malware/ransom.win32.cryptinject"
    },
    {
      "name": "MITRE ATT&CK - Process Injection: Process Hollowing (T1055.012)",
      "url": "https://attack.mitre.org/techniques/T1055/012/"
    }
  ],
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows Server 2022",
    "Windows Server 2019"
  ]
}