{
  "family": "killmbr",
  "sample_count": 1,
  "category": "ransomware",
  "description": "Trojan:Win32/Killmbr (or KillDisk) is a classification for destructive 'Wiper' malware whose primary function is to obliterate the Master Boot Record (MBR) (`T1561.002`) and/or the Master File Table (MFT). Unlike ransomware, which encrypts data to extort money, the sole purpose of a wiper is sabotage—to render the host completely unbootable and the data permanently unrecoverable.<br><br><b>Understanding Killmbr (Destructive Wiper)</b><br>To an end-user, the machine suddenly blue-screens and upon reboot, displays a 'Missing Operating System' or a custom, mocking message from the attackers. For a SOC analyst, a wiper attack is a worst-case scenario, often deployed by nation-state actors (like the NotPetya or HermeticWiper attacks) to disrupt critical infrastructure or deployed by ransomware gangs to cover their tracks if a victim refuses to pay.<br><br><b>Execution and Destruction Mechanics</b><br>To execute its destructive payload, Killmbr *must* obtain high-level administrative or SYSTEM privileges (`T1068`). Once elevated, it uses low-level Windows APIs (like `DeviceIoControl`) to open a direct handle to the physical hard drive (e.g., `\\\\.\\PhysicalDrive0`). It then overwrites the first sector (Sector 0, the MBR) with zeroes or random garbage. Advanced variants will also overwrite the MFT and the partition tables. When the machine inevitably reboots (often forced by the malware), the BIOS cannot locate the bootloader, effectively bricking the OS.<br><br><b>Indicators of Compromise & Impact</b><br>The impact is a total loss of system availability and data. Host-based IoCs include EDR alerts for a process attempting to open a handle to `\\\\.\\PhysicalDrive0` with write permissions. Attackers often use living-off-the-land tools like `vssadmin.exe` to delete shadow copies before initiating the wipe. Once the wipe occurs, the primary indicator is the physical inability to boot the machine.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Killmbr and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Killmbr 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 Killmbr establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Killmbr 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 Killmbr compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Killmbr 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 Killmbr employ during execution?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Killmbr 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 Killmbr, and what is the recommended recovery procedure?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decryption availability for Killmbr 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": [
    "T1561.002",
    "T1529",
    "T1485"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1561.002",
      "name": "Disk Wipe: Disk Structure Wipe (Overwriting the MBR to prevent booting)",
      "tactic": "Impact"
    },
    {
      "id": "T1485",
      "name": "Data Destruction (Overwriting files and the MFT)",
      "tactic": "Impact"
    },
    {
      "id": "T1529",
      "name": "System Shutdown/Reboot (Forcing a restart to trigger the unbootable state)",
      "tactic": "Impact"
    }
  ],
  "containment_steps": [
    "If a wiper attack is suspected and currently in progress, IMMEDIATELY power off the machine (hard shutdown) to halt the overwriting process.",
    "Do not attempt to reboot the machine normally; boot from a forensic live USB or WinPE environment to assess the damage.",
    "If only the MBR is overwritten, use tools like `bootrec /fixmbr` (though advanced wipers destroy the partition table as well).",
    "Restore the system from an offline, read-only backup."
  ],
  "what_to_avoid": [
    "Do not perform a graceful shutdown if you suspect a wiper; simply pull the power cord to preserve whatever data hasn't been overwritten yet.",
    "Avoid relying solely on Volume Shadow Copies for recovery, as wipers almost universally delete these first."
  ],
  "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"
  ]
}