Added DNS flood alert (#5905)

scripts/lua/modules/alert_definitions/host/host_alert_dns_flood.lua

@@ -0,0 +1,91 @@
+--
+-- (C) 2019-22 - ntop.org
+--
+
+-- ##############################################
+
+local host_alert_keys = require "host_alert_keys"
+
+local json = require("dkjson")
+local alert_creators = require "alert_creators"
+
+-- Import the classes library.
+local classes = require "classes"
+-- Make sure to import the Superclass!
+local alert = require "alert"
+
+-- ##############################################
+
+local host_alert_dns_flood = classes.class(alert)
+
+-- ##############################################
+
+host_alert_dns_flood.meta = {
+  alert_key = host_alert_keys.host_alert_dns_flood,
+  i18n_title = "alerts_dashboard.dns_flood",
+  icon = "fas fa-fw fa-life-ring",
+  has_attacker = true,
+}
+
+-- ##############################################
+
+-- @brief Prepare an alert table used to generate the alert
+-- @param one_param The first alert param
+-- @param another_param The second alert param
+-- @return A table with the alert built
+function host_alert_dns_flood:init(metric, value, operator, threshold)
+   -- Call the parent constructor
+   self.super:init()
+
+   self.alert_type_params = alert_creators.createThresholdCross(metric, value, operator, threshold)
+end
+
+-- #######################################################
+
+-- @brief Format an alert into a human-readable string
+-- @param ifid The integer interface id of the generated alert
+-- @param alert The alert description table, including alert data such as the generating entity, timestamp, granularity, type
+-- @param alert_type_params Table `alert_type_params` as built in the `:init` method
+-- @return A human-readable string
+function host_alert_dns_flood.format(ifid, alert, alert_type_params)
+  local alert_consts = require "alert_consts"
+  local entity = alert_consts.formatHostAlert(ifid, alert["ip"], alert["vlan_id"])
+  local i18n_key
+
+  if alert_type_params.is_attacker then
+    i18n_key = "alert_messages.dns_flood_attacker"
+  else
+    i18n_key = "alert_messages.dns_flood_victim"
+  end
+
+  return i18n(i18n_key, {
+    entity = entity,
+    value = string.format("%u", math.ceil(alert_type_params.value or 0)),
+    threshold = alert_type_params.threshold or 0,
+  })
+end
+
+-- #######################################################
+
+-- @brief Prepare a table containing a set of filters useful to query historical flows that contributed to the generation of this alert
+-- @param ifid The integer interface id of the generated alert
+-- @param alert The alert description table, including alert data such as the generating entity, timestamp, granularity, type
+-- @param alert_type_params Table `alert_type_params` as built in the `:init` method
+-- @return A human-readable string
+function host_alert_dns_flood.filter_to_past_flows(ifid, alert, alert_type_params)
+   local res = {}
+   local host_key = hostinfo2hostkey({ip = alert["ip"], vlan = alert["vlan_id"]})
+
+   -- Filter by client or server, depending on whether this alert is as-client or as-server
+   if alert["is_client"] == true or alert["is_client"] == "1" then
+      res["cli_ip"] = host_key
+   elseif alert["is_server"] == true or alert["is_server"] == "1" then
+      res["srv_ip"] = host_key
+   end
+
+   return res
+end
+
+-- #######################################################
+
+return host_alert_dns_flood