{
  "family": "vkhost",
  "sample_count": 2,
  "category": "trojan",
  "description": "Trojan:Win32/Vkhost is a specialized trojan and browser hijacker designed specifically to target users of 'VKontakte' (VK), the massively popular Russian social media platform. Its primary objective is to forcibly redirect the user's browser traffic intended for the legitimate VK site to phishing pages or servers controlled by the attacker, usually to steal login credentials or propagate spam.<br><br><b>Understanding Vkhost (Social Media Hijackers)</b><br>To an end-user, the infection becomes apparent when they attempt to log into `vk.com`. They may be presented with a fake login page that looks identical to the real one, or they may be served aggressive advertisements instead of their news feed. For a security analyst, this malware demonstrates the persistent abuse of local DNS resolution files (`T1562.002`) to bypass network-level security controls.<br><br><b>Execution and Hijacking Mechanics</b><br>Vkhost is typically distributed via deceptive software bundles, fake browser updates, or malicious links shared on social media. Upon execution, the malware requires administrative privileges. Its core functionality is incredibly simple but highly effective: it modifies the Windows `HOSTS` file (`C:\\Windows\\System32\\drivers\\etc\\hosts`). By adding entries mapping `vk.com` and related domains to a malicious IP address, the malware intercepts the DNS resolution process at the host level (`T1562.002`). When the user types `vk.com`, the browser connects to the attacker's server instead of the legitimate VK infrastructure. It often establishes persistence via Registry Run keys (`T1547.001`) to ensure the HOSTS file entries are re-injected if the user attempts to remove them.<br><br><b>Indicators of Compromise & Impact</b><br>The impact is the theft of the user's social media identity, leading to potential secondary phishing attacks against their network. Host-based IoCs are definitive: EDR alerts for a process modifying the `HOSTS` file, and the presence of entries in the `HOSTS` file routing `vk.com` to unknown IP addresses. Network IoCs include the browser attempting to establish an HTTPS connection to the malicious IP, which will often result in a certificate error (as the attacker's server cannot present a valid SSL certificate for `vk.com`).",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Vkhost and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Vkhost is classified as a Trojan. 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 Vkhost establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Vkhost 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 Vkhost compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Vkhost 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 secondary payloads and staging behaviors are commonly associated with Vkhost?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Vkhost frequently operates as a loader or dropper designed to establish a foothold before downloading and executing secondary high-impact malware payloads. Depending on the threat actor's objectives, these dropped modules can range from ransomware and banking injects to modular infostealers and remote management backdoors."
      }
    },
    {
      "@type": "Question",
      "name": "How can security operations teams effectively detect and hunt for Vkhost across enterprise endpoints?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Defenders should hunt for Vkhost by deploying behavioral endpoint detection and response (EDR) rules that monitor suspicious process spawning (such as cmd.exe or powershell.exe spawned from office documents or temporary directories), anomalous outbound network connections from non-browser binaries, and unauthorized modifications to Windows Run keys and scheduled task registries."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1112",
    "T1562.002",
    "T1056.002"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1562.002",
      "name": "Impair Defenses: Disable Windows Event Logging (Modifying the HOSTS file to redirect traffic)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1112",
      "name": "Modify Registry (Establishing persistence to protect the HOSTS file modifications)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1056.002",
      "name": "Input Capture: GUI Input Capture (Stealing credentials via the phishing overlay)",
      "tactic": "Collection"
    }
  ],
  "containment_steps": [
    "Open the `C:\\Windows\\System32\\drivers\\etc\\hosts` file using a text editor running with Administrator privileges and delete the malicious VK entries.",
    "Run a full system scan to locate and remove the core Vkhost executable that is protecting the HOSTS file.",
    "Use a clean, separate device to immediately change the password for the compromised VK account and enable two-factor authentication.",
    "Clear the local DNS cache (`ipconfig /flushdns`) to ensure the browser routes to the correct infrastructure."
  ],
  "what_to_avoid": [
    "Do not ignore SSL certificate warnings in the browser; if a major site like VK suddenly presents a certificate error, it is likely being hijacked.",
    "Avoid relying solely on network-level DNS filtering to block this threat, as the local HOSTS file overrides external DNS resolution."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "execution",
    "persistence"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows 7"
  ]
}