Migrates alerts to an object-oriented implementation

scripts/lua/modules/alert_definitions/alert_lateral_movement.lua

@@ -2,50 +2,37 @@
 -- (C) 2019-20 - ntop.org
 --
 
--- ##############################################
+local alert_keys   = require "alert_keys"
+local format_utils = require "format_utils"
+local json         = require("dkjson")
 
-local alert_keys = require "alert_keys"
--- Import the classes library.
-local classes = require "classes"
--- Make sure to import the Superclass!
-local alert = require "alert"
-
--- ##############################################
-
-local alert_lateral_movement = classes.class(alert)
-
--- ##############################################
-
-alert_lateral_movement.meta = {
-   alert_key = alert_keys.ntopng.alert_lateral_movement,
-   i18n_title = "alerts_dashboard.lateral_movement",
-   icon = "fas fa-arrows-alt-h",
-}
-
--- ##############################################
+-- #######################################################
 
 -- @brief Prepare an alert table used to generate the alert
+-- @param alert_severity A severity as defined in `alert_severities`
+-- @param alert_granularity A granularity as defined in `alert_consts.alerts_granularities`
 -- @param last_error A table containing the last lateral movement error, e.g.,
 --                   {"event":"create","shost":"192.168.2.153","dhost":"224.0.0.68","dport":1968,"vlan_id":0,"l4":17,"l7":0,"first_seen":1602488355,"last_seen":1602488355,"num_uses":1}
 -- @return A table with the alert built
-function alert_lateral_movement:init(last_error)
-   -- Call the paren constructor
-   self.super:init()
-
-   self.alert_type_params = {
-      error_msg = last_error
+local function createLateralMovementError(alert_severity, alert_granularity, last_error)
+   -- Create a subtype, to avoid merging multiple lateral movement alerts together
+   local alert_subtype = last_error.shost .. "/" .. last_error.dhost .. "/" .. last_error.dport .. "/" .. last_error.l4 .. "/" .. last_error.l7
+   local threshold_type = {
+      alert_severity = alert_severity,
+      alert_subtype = alert_subtype,
+      alert_granularity = alert_granularity,
+      alert_type_params = {
+	 error_msg = last_error
+      },
    }
+
+   return threshold_type
 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 alert_lateral_movement.format(ifid, alert, alert_type_params)
-   local msg = alert_type_params.error_msg
+local function formatLateralMovementErrorMessage(ifid, alert, status)
+   local msg = status.error_msg
    local vlan_id = msg.vlan_id or 0
    local client = {host = msg.shost, vlan = vlan_id}
    local server = {host = msg.dhost, vlan = vlan_id}
@@ -54,15 +41,21 @@ function alert_lateral_movement.format(ifid, alert, alert_type_params)
       " <i class=\"fas fa-exchange-alt fa-lg\" aria-hidden=\"true\" data-original-title=\"\" title=\"\"></i> " ..
       hostinfo2detailshref(server, nil, hostinfo2label(server))..
       " ["..i18n("port")..": "..msg.dport.."]"
-
+   
    rsp = rsp .. "["..i18n("application")..": "..interface.getnDPIProtoName(msg.l7).."]"
    if not isEmptyString(msg.info) then
       rsp = rsp .. "[" .. msg.info .. "]"
    end
-
+   
    return(rsp)
 end
 
 -- #######################################################
 
-return alert_lateral_movement
+return {
+  alert_key = alert_keys.ntopng.alert_lateral_movement,
+  i18n_title = "alerts_dashboard.lateral_movement",
+  i18n_description = formatLateralMovementErrorMessage,
+  icon = "fas fa-arrows-alt-h",
+  creator = createLateralMovementError,
+}