{
  "family": "cryptexe",
  "sample_count": 2,
  "category": "ransomware",
  "description": "Trojan:Win32/Cryptexe is a generic detection frequently applied to malware that utilizes sophisticated software packing, encryption, or obfuscation tools ('crypters') to conceal its true payload (`T1027.002`). The primary goal of a crypter is to alter the file signature of a known malware sample (like a RAT or infostealer) so that it can bypass static, signature-based antivirus scanning at the perimeter.<br><br><b>Understanding Cryptexe (Crypters & Packers)</b><br>To an end-user, the infection appears as a normal file execution, followed immediately by the symptoms of the hidden payload. For security analysts, a 'Cryptexe' detection indicates that the AV engine recognized the obfuscation technique (the 'wrapper') but may not know exactly what the inner payload is until it executes in memory. Crypters are a foundational component of the Cybercrime-as-a-Service economy, sold specifically to help malware authors evade detection.<br><br><b>Execution and Evasion Mechanics</b><br>When the Cryptexe executable runs, the entry point points to a decryption 'stub'. This stub allocates memory (`VirtualAlloc`), decrypts the actual malicious payload from the file's resource section or data sections, and then executes it. Often, this involves 'Process Hollowing' (`T1055.012`)—launching a legitimate process like `svchost.exe`, hollowing out its memory, and injecting the decrypted payload into it. The original packed file on disk never contains the raw malicious code, rendering static analysis useless without unpacking.<br><br><b>Indicators of Compromise & Impact</b><br>The impact is entirely dependent on the decrypted payload (ransomware, spyware, etc.). Host-based IoCs include EDR alerts for 'Suspicious API Calls' (e.g., `CreateRemoteThread`, `WriteProcessMemory`), 'Process Hollowing', or executables with unusually high entropy (indicating encryption or compression). Network IoCs will be specific to the C2 infrastructure of the hidden payload.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1105",
    "T1055.012",
    "T1027.002"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1027.002",
      "name": "Obfuscated Files or Information: Software Packing (Using a crypter to hide the payload)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1055.012",
      "name": "Process Injection: Process Hollowing (Executing the decrypted payload in memory)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1105",
      "name": "Ingress Tool Transfer (Downloading the initial packed executable)",
      "tactic": "Command and Control"
    }
  ],
  "containment_steps": [
    "Isolate the endpoint. The critical threat is the payload executing in memory, not the packed shell on disk.",
    "Capture a live memory image (RAM dump). This is the only reliable way to extract the decrypted payload for reverse engineering and IoC extraction.",
    "Utilize EDR telemetry to identify the original execution vector (e.g., a phishing email) to block the delivery mechanism.",
    "Hunt for related files based on the packer's specific stub characteristics (e.g., Imphash) rather than standard file hashes."
  ],
  "what_to_avoid": [
    "Do not rely on standard file hashes (MD5/SHA256) of the Cryptexe file for sweeping the network; attackers re-pack files constantly to change the hash.",
    "Avoid relying solely on static analysis; dynamic analysis (sandboxing) or memory forensics is required to understand the threat."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}