{
  // Linux syslog/auditd parser — OCSF v1.3.0
  attributes: {
    "metadata.version":             "1.3.0",
    "metadata.product.vendor_name": "Linux",
    "metadata.product.name":        "Linux OS",
    "metadata.log_provider":        "syslog",
    "Category":               "host",
    "dataSource.vendor":      "Linux",
    "dataSource.name":        "Linux OS",
    "dataSource.category":    "host",
    "category_uid":           1,
    "category_name":          "System Activity",
    "class_uid":              1001,
    "class_name":             "File System Activity",
    "activity_id":            0,
    "activity_name":          "Unknown",
    "type_uid":               100100,
    "status_id":              1,
    "status":                 "Success",
    "severity_id":            1,
    "severity":               "Informational"
  },

  patterns: {
    ipv4:   "\\d+\\.\\d+\\.\\d+\\.\\d+",
    word:   "\\S+",
    rest:   ".*",
    creds:  "(mimikatz|hashdump|secretsdump|kerbrute)",
    revshell: ".*socket\\.socket.*"
  },

  formats: [
    // SSH failed authentication
    {
      id: "ssh_failed",
      attributes: {
        class_uid: 2004, class_name: "Detection Finding",
        category_uid: 2, category_name: "Findings",
        activity_id: 1, activity_name: "Create",
        type_uid: 200401,
        finding_title: "Linux SSH Authentication Failure",
        severity_id: 4, severity: "High",
        disposition_id: 2, disposition: "Blocked"
      },
      format: ".*Failed password for $user_name=word$ from $src_ip=ipv4$ port $src_port=word$.*",
      halt: true
    },

    // SSH successful authentication
    {
      id: "ssh_success",
      attributes: {
        class_uid: 3002, class_name: "Authentication",
        category_uid: 3, category_name: "IAM",
        activity_id: 1, activity_name: "Logon",
        type_uid: 300201,
        status_id: 1, status: "Success"
      },
      format: ".*Accepted password for $user_name=word$ from $src_ip=ipv4$ port $src_port=word$.*",
      halt: true
    },

    // sudo NOT in sudoers (priv-esc attempt)
    {
      id: "sudo_not_in_sudoers",
      attributes: {
        class_uid: 2004, class_name: "Detection Finding",
        category_uid: 2, category_name: "Findings",
        activity_id: 1, activity_name: "Create",
        type_uid: 200401,
        finding_title: "Linux Sudo Not In Sudoers",
        severity_id: 5, severity: "Critical",
        disposition_id: 2, disposition: "Blocked"
      },
      format: ".*sudo: $user_name=word$ : user NOT in sudoers ; TTY=$tty=word$ ; PWD=$pwd=word$ ; USER=$target_user=word$ ; COMMAND=$process_cmd_line=rest$",
      halt: true
    },

    // useradd — new user account created
    {
      id: "useradd",
      attributes: {
        class_uid: 3001, class_name: "Account Change",
        category_uid: 3, category_name: "IAM",
        activity_id: 1, activity_name: "Create",
        type_uid: 300101,
        finding_title: "Linux New User Account Created",
        severity_id: 4, severity: "High"
      },
      format: ".*useradd\\[$pid=word$\\]: new user: name=$new_user=word$, UID=$uid=word$, GID=$gid=word$.*",
      halt: true
    },

    // Mimikatz / credential dumping signatures
    {
      id: "credential_dump",
      attributes: {
        class_uid: 2004, class_name: "Detection Finding",
        category_uid: 2, category_name: "Findings",
        type_uid: 200401,
        finding_title: "Linux Credential Dumping Tool",
        severity_id: 5, severity: "Critical",
        disposition_id: 2, disposition: "Blocked"
      },
      format: ".*$tool=creds$.*",
      halt: true
    },

    // Reverse shell (python -c socket)
    {
      id: "reverse_shell",
      attributes: {
        class_uid: 2004, class_name: "Detection Finding",
        category_uid: 2, category_name: "Findings",
        type_uid: 200401,
        finding_title: "Linux Reverse Shell Execution",
        severity_id: 5, severity: "Critical",
        disposition_id: 2, disposition: "Blocked"
      },
      format: ".*python$ver=word$ -c $cmd=revshell$.*",
      halt: true
    },

    // Generic auditd EXECVE
    {
      id: "auditd_execve",
      attributes: {
        class_uid: 1007, class_name: "Process Activity",
        category_uid: 1, category_name: "System Activity",
        activity_id: 1, activity_name: "Launch",
        type_uid: 100701
      },
      format: ".*auditd\\[$pid=word$\\]: EXECVE argc=$argc=word$ a0=\"$process_name=word$\" $cmdline=rest$",
      halt: true
    },

    // Cron job executed (suspicious if from /tmp/.hidden)
    {
      id: "cron_suspicious",
      attributes: {
        class_uid: 2004, class_name: "Detection Finding",
        category_uid: 2, category_name: "Findings",
        type_uid: 200401,
        finding_title: "Linux Suspicious Cron Job",
        severity_id: 4, severity: "High"
      },
      format: ".*cron\\[$pid=word$\\]: \\($cron_user=word$\\) CMD \\($cron_cmd=rest$\\)",
      halt: true
    }
  ]
}