{
  "model_id": "SOC.004",
  "name": "SSH Key Dropped For New User",
  "description": "Authorized_keys entry added for a user created in the same window.",
  "threshold": 0.85,
  "evaluations": [
    {
      "name": "KeyAdd",
      "type": "comparison",
      "left": "event.type",
      "operator": "==",
      "right": "sshkey.added",
      "weight": 4
    },
    {
      "name": "UserCreated",
      "type": "comparison",
      "left": "event.type",
      "operator": "==",
      "right": "identity.user.created",
      "weight": 4
    },
    {
      "name": "Logic",
      "type": "logical",
      "operator": "AND",
      "operands": [
        "KeyAdd",
        "UserCreated"
      ],
      "weight": 5
    }
  ],
  "actions": [
    {
      "type": "emit_alert",
      "reason": "SSH backdoor: key added for new user {event.actor.user}."
    }
  ],
  "mitre_tactics": [
    "Persistence",
    "Credential Access"
  ],
  "mitre_techniques": [
    "T1098",
    "T1136"
  ],
  "severity": "critical",
  "observables": [
    "event.actor.user"
  ]
}