{
  "family": "eskimo",
  "sample_count": 1,
  "category": "ransomware",
  "description": "Backdoor:Win32/Eskimo is a persistent Remote Access Trojan (RAT) designed to provide attackers with covert, interactive control over a compromised system. True to its name, Eskimo focuses heavily on stealth and espionage, allowing operators to exfiltrate sensitive documents, monitor user activity, and maintain a long-term presence within a network without triggering traditional alarms (`T1059`).<br><br><b>Understanding Eskimo (Covert Backdoor)</b><br>To an end-user, the infection is entirely invisible. For an incident response team, the presence of Eskimo indicates a targeted attack or an advanced persistent threat (APT) scenario, where the adversary is prioritizing intelligence gathering and lateral movement over immediate, noisy monetization (like ransomware).<br><br><b>Execution and Covert Mechanics</b><br>Eskimo is typically delivered via highly targeted spearphishing campaigns or dropped after initial exploitation of a vulnerable web service. Upon execution, it employs advanced evasion techniques, often utilizing API unhooking or direct syscalls to bypass EDR monitoring (`T1562.001`). It establishes persistence covertly, sometimes utilizing DLL Search Order Hijacking (`T1574.001`) or WMI event subscriptions (`T1546.003`) rather than noisy Registry Run keys. It communicates with its C2 server using customized, encrypted protocols, often blending in with normal HTTPS or DNS traffic (`T1071.001`) to evade network intrusion detection systems.<br><br><b>Indicators of Compromise & Impact</b><br>The primary impact is the severe loss of confidentiality and intellectual property theft. Host-based IoCs require deep forensics: EDR alerts for anomalous DLL loads, unusual WMI activity, or legitimate processes (like `svchost.exe`) making unexpected network connections. Network IoCs are subtle, often manifesting as regular, low-volume 'beaconing' traffic to unknown IP addresses or domains with recently registered, anomalous names.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1574.001",
    "T1005",
    "T1059",
    "T1071.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1059",
      "name": "Command and Scripting Interpreter (Providing covert shell access)",
      "tactic": "Execution"
    },
    {
      "id": "T1574.001",
      "name": "Hijack Execution Flow: DLL Search Order Hijacking (Covert persistence mechanism)",
      "tactic": "Persistence"
    },
    {
      "id": "T1071.001",
      "name": "Application Layer Protocol: Web Protocols (Blending C2 traffic with normal HTTPS)",
      "tactic": "Command and Control"
    },
    {
      "id": "T1005",
      "name": "Data from Local System (Covertly searching for and staging sensitive files)",
      "tactic": "Collection"
    }
  ],
  "containment_steps": [
    "Isolate the machine immediately to sever the attacker's interactive control and halt data exfiltration.",
    "Assume all credentials present on the machine have been compromised and initiate an immediate, enterprise-wide password reset for the affected user.",
    "Capture a full memory dump (RAM) before remediation to analyze the decrypted Eskimo configuration and identify its specific C2 infrastructure.",
    "Hunt for the identified C2 IPs and domains across firewall logs to determine if the attacker successfully pivoted to other endpoints."
  ],
  "what_to_avoid": [
    "Do not assume the attack is contained to a single machine; backdoors like Eskimo are primarily used as beachheads for lateral movement.",
    "Avoid relying solely on automated AV removal, as the attacker likely established secondary, manual persistence mechanisms."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}