ntopng/scripts/lua/modules/check_definitions/host/suspicious_domain_scan.lua
Alfredo Cardigliano 2c1908b43e Fix dup condition
2025-02-19 09:47:19 +01:00

140 lines
4.1 KiB
Lua

--
-- (C) 2019-24 - ntop.org
--
-- Check notes:
-- This check implements a periodic Lua check for triggering host alerts
-- Please note this actually runs periodically on an interface and should be used
-- to run queries on the database or scan hosts, it is NOT called for each host.
-- Only store() should be used, trigger/release (engaged alerts) are not supported
local checks = require("checks")
local alerts_api = require "alerts_api"
local alert_consts = require("alert_consts")
local host_alert_keys = require "host_alert_keys"
local alert_entities = require "alert_entities"
-- #################################################################
local script = {
edition = "enterprise_m",
category = checks.check_categories.security,
severity = alert_consts.get_printable_severities().error,
alert_id = host_alert_keys.host_alert_suspicious_domain_scan,
-- This module is disabled by default
default_enabled = false,
-- Default value (reset with "Reset Default" button)
default_value = {
operator = "gt",
threshold = 100,
},
gui = {
i18n_title = "flow_checks.suspicious_domain_scan_title",
i18n_description = "flow_checks.suspicious_domain_scan_description",
i18n_field_unit = checks.field_units.domains,
input_builder = "threshold_cross",
field_min = 1,
field_max = 1000,
field_operator = "gt";
},
hooks = {},
}
-- #################################################################
-- Generate alert (store)
local function report_host(params, ip, vlan, victim, num_domains)
local hostinfo = {
host = ip,
vlan = vlan
}
local descr = ""
local score = 100
local alert = alert_consts.alert_types.host_alert_suspicious_domain_scan.new(
interface.getId(),
victim,
num_domains
)
local host_key = hostinfo2hostkey(hostinfo)
alert:set_subtype(host_key)
alert:set_score(score)
alert:set_category(checks.check_categories.security)
alert:set_info(params)
local alert_info = {
entity_val = host_key,
alert_entity = alert_entities.host
}
alert:store(alert_info)
end
-- #################################################################
-- Check number of domains contacted by an host towards another host
local function domains_check(params)
-- Settings
local threshold = tonumber(params.check_config.threshold) or script.default_value.threshold
local interval_size = 60*60 -- 1 hour
if not ntop.isClickHouseEnabled() then
return
end
local now = os.time()
local interval_begin = now - interval_size
local interval_end = now
local q = string.format(
"SELECT f.ip_src_4, f.ip_src_6, f.ip_dst_4, f.ip_dst_6, count FROM ("
.. "SELECT "
.. "VLAN_ID vlan_id, "
.. "IPv4NumToString(IPV4_SRC_ADDR) ip_src_4, "
.. "IPv6NumToString(IPV6_SRC_ADDR) ip_src_6, "
.. "IPv4NumToString(IPV4_DST_ADDR) ip_dst_4, "
.. "IPv6NumToString(IPV6_DST_ADDR) ip_dst_6, "
.. "COUNT(DISTINCT DOMAIN_NAME) AS count "
.. "FROM flows "
.. "WHERE INTERFACE_ID=%u "
.. "AND DOMAIN_NAME!='' "
.. "AND (L7_PROTO!=5 AND L7_PROTO_MASTER!=5) "
.. "AND (FIRST_SEEN >= %u AND FIRST_SEEN <= %u AND LAST_SEEN <= %u) "
.. "GROUP BY VLAN_ID, IPV4_SRC_ADDR, IPV6_SRC_ADDR, IPV4_DST_ADDR, IPV6_DST_ADDR "
.. "ORDER BY count DESC "
.. ") f WHERE f.count > %u",
tonumber(interface.getId()),
interval_begin, interval_end, interval_end,
threshold
)
local results = interface.execSQLQuery(q)
for _, row in ipairs(results) do
local count = tonumber(row.count) or 0
local vlan_id = tonumber(row.vlan_id) or 0
local ip = row.ip_src_4
if row.ip_src_6 and row.ip_src_6 ~= '::' then ip = row.ip_src_6 end
local victim_ip = row.ip_dst_4
if row.ip_dst_6 and row.ip_dst_6 ~= '::' then victim_ip = row.ip_dst_6 end
report_host(params, ip, vlan_id, victim_ip, count)
end
end
-- #################################################################
script.hooks.hour = domains_check
-- #################################################################
return script