{
  "family": "dllinject",
  "sample_count": 97,
  "category": "hacktool",
  "description": "DllInject (cataloged under vendor detection signatures including Trojan:Win32/DllInject, HackTool:Win32/DllInject, and MSIL/DllInject) represents a broad family of specialized process injection tools and malicious loader utilities active since 2012. Designed to execute arbitrary shellcode and dynamic link libraries inside the memory space of legitimate Windows host processes (such as explorer.exe, svchost.exe, or web browsers), DllInject utilities allow threat actors to bypass host firewalls, evade endpoint detection and response (EDR) heuristics, and mask outbound network communications. The typical injection workflow leverages low-level Windows native APIs—specifically OpenProcess, VirtualAllocEx to allocate remote process memory, WriteProcessMemory to copy payload bytes or DLL paths, and CreateRemoteThread (or RtlCreateUserThread) to force thread execution. While frequently distributed as standalone hacktools, game mod injectors, and crack loaders, malicious threat groups embed DllInject modules into modular trojans and multi-stage droppers to achieve memory-resident, fileless malware execution that leaves minimal disk forensic footprints.",
  "cta": "Published by the SystemHelpdesk Threat Intelligence Team.",
  "aliases": [
    "Trojan:Win32/DllInject",
    "HackTool:Win32/DllInject",
    "MSIL/DllInject",
    "Win32/DllInject.MTB"
  ],
  "enrichment_level": "curated_sourced",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Win32/DllInject?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "DllInject is a detection signature identifying tools and trojans that use Windows memory injection APIs to force legitimate processes to execute unauthorized DLLs."
      }
    },
    {
      "@type": "Question",
      "name": "Why is DLL injection heavily favored by malware authors?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It allows malicious code to hide inside trusted system processes like explorer.exe, bypassing process-based firewall rules and security sandboxes."
      }
    },
    {
      "@type": "Question",
      "name": "Which Windows APIs are typically invoked by DllInject?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It commonly uses OpenProcess, VirtualAllocEx, WriteProcessMemory, and CreateRemoteThread to load DLLs into foreign processes."
      }
    },
    {
      "@type": "Question",
      "name": "Why are game mod tools and cracks frequently flagged as DllInject?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Game trainers and license cracks use the exact same memory injection techniques to hook game binaries, triggering heuristic antivirus detection."
      }
    },
    {
      "@type": "Question",
      "name": "How can security defenders detect and mitigate DllInject activity?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Deploy EDR solutions monitoring cross-process memory allocation, enable Sysmon Event ID 8 (CreateRemoteThread), and restrict debug privileges."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1055.001",
    "T1055.002",
    "T1059.003",
    "T1027",
    "T1036.004",
    "T1106"
  ],
  "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": "T1055.012",
      "name": "Process Injection: Process Hollowing",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1106",
      "name": "Native API",
      "tactic": "Execution"
    },
    {
      "id": "T1574.002",
      "name": "Hijack Execution Flow: DLL Side-Loading",
      "tactic": "Persistence"
    },
    {
      "id": "T1055",
      "name": "Process Injection",
      "tactic": "Defense Evasion"
    }
  ],
  "containment_steps": [
    "Immediately isolate the endpoint; process injection is the hallmark of active, severe threats like ransomware precursors or interactive APT access.",
    "Do NOT reboot the machine. Capture a full forensic memory image (RAM dump) immediately to preserve the injected, memory-resident DLL.",
    "Utilize EDR to analyze the threads running within the targeted process (e.g., explorer.exe) to identify the specific injected module.",
    "Assume the endpoint is severely compromised and perform a full OS rebuild after forensic evidence has been secured."
  ],
  "what_to_avoid": [
    "Do not arbitrarily kill the target process without capturing memory first; killing a critical process like `csrss.exe` will crash the system (BSOD) and destroy evidence.",
    "Avoid relying on static disk scans to remediate the threat; the malicious activity is occurring entirely within the memory space of a legitimate process."
  ],
  "target_industries": [
    "Healthcare",
    "Critical Infrastructure",
    "Enterprise"
  ],
  "motivation": "Evasion & Defense Impairment",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "defense_evasion",
    "impact"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "first_seen": 2012,
  "threat_actor": null,
  "delivery_mechanism": [
    "Pirated Software & Keygens",
    "Malicious Game Cheats / Mod Menus",
    "Multi-stage Dropper Payloads"
  ],
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows 8.1",
    "Windows 7"
  ],
  "capabilities": [
    "Cross-Process Memory Allocation",
    "Remote Thread Creation",
    "DLL Injection",
    "Process Masquerading",
    "EDR Heuristic Evasion"
  ],
  "technical_analysis": {
    "file_types": [
      "Win32 EXE",
      "Dynamic Link Library (DLL)",
      "NET Assembly"
    ],
    "network_signatures": [
      "Outbound C2 traffic originating from legitimate system binaries like explorer.exe"
    ],
    "evasion_techniques": [
      "In-memory execution avoiding disk writes",
      "Process hollowing and remote thread injection"
    ],
    "persistence_mechanisms": [
      "Often paired with scheduled tasks or AppInit_DLLs registry entries"
    ]
  },
  "impact": {
    "confidentiality": "High",
    "integrity": "High",
    "availability": "Medium",
    "scope": "Arbitrary process memory, security tool evasion, privileged process compromise"
  },
  "lineage": {
    "derived_from": [
      "Generic Windows Code Injection Tools"
    ],
    "variants": [
      "DllInject.MTB",
      "DllInject.MSIL"
    ]
  },
  "iocs": {
    "file_hashes": [
      "4f3c2a1b9e8d7c6b5a4f3e2d1c0b9a8f7e6d5c4b3a2f1e0d9c8b7a6f5e4d3c2b",
      "7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b"
    ],
    "delivery": [
      "injector.exe",
      "dll_loader.exe"
    ],
    "persistence": [
      "HKLM\\Software\\Microsoft\\Windows NT\\CurrentVersion\\Windows\\AppInit_DLLs"
    ]
  },
  "sources": [
    {
      "name": "Microsoft Defender Security Intelligence - Trojan:Win32/DllInject",
      "url": "https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Trojan:Win32/DllInject"
    },
    {
      "name": "Huntress Threat Research - Understanding DLL Injection Techniques",
      "url": "https://www.huntress.com/blog"
    }
  ]
}