{
  "family": "ranserkd",
  "sample_count": 5,
  "category": "ransomware",
  "description": "Ransom:Win32/Ranserkd is a highly destructive ransomware variant designed to systematically encrypt all valuable data on an infected endpoint or network share, followed by an extortion demand. It utilizes strong cryptographic algorithms (typically AES combined with RSA) to ensure that recovering the locked files is mathematically impossible without paying the attackers for the unique private decryption key.<br><br><b>Understanding the Ranserkd Threat</b><br>To a victim, a Ranserkd infection represents a catastrophic loss of data; documents, databases, and photos become inaccessible, appended with a strange file extension, and a ransom note appears on the desktop. For an enterprise, it triggers a critical incident response involving total network isolation to prevent the ransomware from spreading to critical servers and backups.<br><br><b>Execution and Encryption Mechanics</b><br>Ranserkd is frequently deployed manually by attackers after they have already breached the network (e.g., via compromised RDP credentials or an Initial Access Broker) (`T1078`), or delivered via massive malspam campaigns (`T1566.001`). Upon execution, the ransomware first attempts to neutralize endpoint defenses and delete Windows Volume Shadow Copies (`vssadmin.exe delete shadows`) to prevent easy data restoration (`T1490`). It then aggressively scans all local drives and mapped network shares, rapidly encrypting files that match a hardcoded list of valuable extensions (e.g., `.docx`, `.sql`, `.pdf`) (`T1486`). Finally, it drops a ransom note (often a `.txt` or `.html` file) detailing payment instructions via cryptocurrency.<br><br><b>Indicators of Compromise & Impact</b><br>The impact is total data denial of service. Host-based IoCs include massive spikes in CPU and disk I/O activity caused by the rapid encryption process. EDR systems will flag the execution of `vssadmin.exe` or `bcdedit.exe` attempting to disable recovery features. Files across the system will suddenly change extensions, and the ransomware executable itself may be found running from the `%Temp%` or `%AppData%` directories.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Ranserkd and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Ranserkd 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."
      }
    },
    {
      "@type": "Question",
      "name": "How does Ranserkd establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Ranserkd 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."
      }
    },
    {
      "@type": "Question",
      "name": "What are the essential incident response steps for mitigating a Ranserkd compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Ranserkd 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."
      }
    },
    {
      "@type": "Question",
      "name": "What cryptographic algorithms and file targeting techniques does Ranserkd employ during execution?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Ranserkd 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."
      }
    },
    {
      "@type": "Question",
      "name": "Are decryptors available for Ranserkd, and what is the recommended recovery procedure?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decryption availability for Ranserkd 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."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1485",
    "T1490",
    "T1078",
    "T1486"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1486",
      "name": "Data Encrypted for Impact",
      "tactic": "Impact"
    },
    {
      "id": "T1490",
      "name": "Inhibit System Recovery (Deleting Shadow Copies)",
      "tactic": "Impact"
    },
    {
      "id": "T1078",
      "name": "Valid Accounts (Common deployment method for enterprise ransomware)",
      "tactic": "Initial Access"
    },
    {
      "id": "T1485",
      "name": "Data Destruction (If encryption is flawed or keys are lost)",
      "tactic": "Impact"
    }
  ],
  "containment_steps": [
    "Immediately sever the infected endpoint from the network (physically pull the Ethernet cable or disable the switch port) to stop it from encrypting mapped network drives.",
    "Do NOT reboot the infected machine; capture a live memory image (RAM dump), as the encryption keys might temporarily reside in memory.",
    "Identify the exact Ranserkd variant and consult resources like 'No More Ransom' to see if a known decryption flaw exists before considering payment.",
    "Restore the encrypted systems from secure, offline backups that were isolated from the network at the time of the attack."
  ],
  "what_to_avoid": [
    "Do not pay the ransom immediately; paying funds criminal syndicates and there is no guarantee the provided decryptor will actually work.",
    "Avoid reconnecting restored machines to the network until the initial entry vector (e.g., a vulnerable VPN or weak RDP password) has been completely secured."
  ],
  "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,
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows Server 2022",
    "Windows Server 2019"
  ]
}