Pi-hole Logs in the HELK Stack

wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -

sudo apt-get install apt-transport-https

sudo apt update -y && sudo apt install filebeat -y

sudo systemctl enable filebeat

###################### Filebeat Configuration Example #########################

# This file is an example configuration file highlighting only the most common
# options. The filebeat.reference.yml file from the same directory contains all the
# supported options with more comments. You can use it as a reference.
#
# You can find the full configuration reference here:
# https://www.elastic.co/guide/en/beats/filebeat/index.html

# For more available modules and options, please see the filebeat.reference.yml sample
# configuration file.

# ============================== Filebeat inputs ===============================

filebeat.inputs:

# Each - is an input. Most options can be set at the input level, so
# you can use different inputs for various configurations.
# Below are the input specific configurations.

- type: log

  # Change to true to enable this input configuration.
  enabled: true

  # Paths that should be crawled and fetched. Glob based paths.
  paths:
    - /var/log/pihole.log
    #- c:\programdata\elasticsearch\logs\*

  # Exclude lines. A list of regular expressions to match. It drops the lines that are
  # matching any regular expression from the list.
  #exclude_lines: ['^DBG']

  # Include lines. A list of regular expressions to match. It exports the lines that are
  # matching any regular expression from the list.
  #include_lines: ['^ERR', '^WARN']

  # Exclude files. A list of regular expressions to match. Filebeat drops the files that
  # are matching any regular expression from the list. By default, no files are dropped.
  #exclude_files: ['.gz$']

  # Optional additional fields. These fields can be freely picked
  # to add additional information to the crawled log files for filtering
  fields:
    level: debug
  #  review: 1

  ### Multiline options

  # Multiline can be used for log messages spanning multiple lines. This is common
  # for Java Stack Traces or C-Line Continuation

  # The regexp Pattern that has to be matched. The example pattern matches all lines starting with [
  #multiline.pattern: ^\[

  # Defines if the pattern set under pattern should be negated or not. Default is false.
  #multiline.negate: false

  # Match can be set to "after" or "before". It is used to define if lines should be append to a pattern
  # that was (not) matched before or after or as long as a pattern is not matched based on negate.
  # Note: After is the equivalent to previous and before is the equivalent to to next in Logstash
  #multiline.match: after

# ============================== Filebeat modules ==============================

filebeat.config.modules:
  # Glob pattern for configuration loading
  path: ${path.config}/modules.d/*.yml

  # Set to true to enable config reloading
  reload.enabled: false

  # Period on which files under path should be checked for changes
  #reload.period: 10s

# ======================= Elasticsearch template setting =======================

setup.template.settings:
  index.number_of_shards: 1
  #index.codec: best_compression
  #_source.enabled: false
setup.template.name: "logs-dns-pihole"
setup.template.pattern: "logs-dns-pihole-*"

# ================================== General ===================================

# The name of the shipper that publishes the network data. It can be used to group
# all the transactions sent by a single shipper in the web interface.
#name:

# The tags of the shipper are included in their own field with each
# transaction published.
tags: ["pihole", "additional tags", "tags that could be specific to a certain locations"]

# Optional fields that you can specify to add additional information to the
# output.
#fields:
#  env: staging

# ================================= Dashboards =================================
# These settings control loading the sample dashboards to the Kibana index. Loading
# the dashboards is disabled by default and can be enabled either by setting the
# options here or by using the `setup` command.
#setup.dashboards.enabled: false

# The URL from where to download the dashboards archive. By default this URL
# has a value which is computed based on the Beat name and version. For released
# versions, this URL points to the dashboard archive on the artifacts.elastic.co
# website.
#setup.dashboards.url:

# =================================== Kibana ===================================

# Starting with Beats version 6.0.0, the dashboards are loaded via the Kibana API.
# This requires a Kibana endpoint configuration.
setup.kibana:

  # Kibana Host
  # Scheme and port can be left out and will be set to the default (http and 5601)
  # In case you specify and additional path, the scheme is required: http://localhost:5601/path
  # IPv6 addresses should always be defined as: https://[2001:db8::1]:5601
  # HELK does not expose :5601 as a domain location, it uses nginx to host the site at :80 or :443
  # host: "example.com/app/kibana"
  host: "YOUR HOST DOMAIN/IP ADDRESS AND PORT FOR KIBANA"

  # Kibana Space ID
  # ID of the Kibana Space into which the dashboards should be loaded. By default,
  # the Default Space will be used.
  #space.id:

# =============================== Elastic Cloud ================================

# These settings simplify using Filebeat with the Elastic Cloud (https://cloud.elastic.co/).

# The cloud.id setting overwrites the `output.elasticsearch.hosts` and
# `setup.kibana.host` options.
# You can find the `cloud.id` in the Elastic Cloud web UI.
#cloud.id:

# The cloud.auth setting overwrites the `output.elasticsearch.username` and
# `output.elasticsearch.password` settings. The format is `<user>:<pass>`.
#cloud.auth:

# ================================== Outputs ===================================

# Configure what output to use when sending the data collected by the beat.

# ---------------------------- Elasticsearch Output ----------------------------
# output.elasticsearch:
  # Array of hosts to connect to.
  # hosts: ["localhost:9200"]

  # Protocol - either `http` (default) or `https`.
  #protocol: "https"

  # Authentication credentials - either API key or username/password.
  #api_key: "id:api_key"
  #username: "elastic"
  #password: "changeme"

# ------------------------------ Logstash Output -------------------------------
output.logstash:
  # The Logstash hosts
  # hosts: ["example.com:5044"]
  hosts: ["YOUR HOST DOMAIN/IP ADDRESS AND PORT FOR LOGSTASH:5601"]

  # Optional SSL. By default is off.
  # List of root certificates for HTTPS server verifications
  #ssl.certificate_authorities: ["/etc/pki/root/ca.pem"]

  # Certificate for SSL client authentication
  #ssl.certificate: "/etc/pki/client/cert.pem"

  # Client Certificate Key
  #ssl.key: "/etc/pki/client/cert.key"

# ================================= Processors =================================
processors:
  - add_host_metadata:
      when.not.contains.tags: forwarded
  - add_cloud_metadata: ~
  - add_docker_metadata: ~
  - add_kubernetes_metadata: ~

# ================================== Logging ===================================

# Sets log level. The default log level is info.
# Available log levels are: error, warning, info, debug
#logging.level: debug

# At debug level, you can selectively enable logging only for some components.
# To enable all selectors use ["*"]. Examples of other selectors are "beat",
# "publish", "service".
#logging.selectors: ["*"]

# ============================= X-Pack Monitoring ==============================
# Filebeat can export internal metrics to a central Elasticsearch monitoring
# cluster.  This requires xpack monitoring to be enabled in Elasticsearch.  The
# reporting is disabled by default.

# Set to true to enable the monitoring reporter.
#monitoring.enabled: false

# Sets the UUID of the Elasticsearch cluster under which monitoring data for this
# Filebeat instance will appear in the Stack Monitoring UI. If output.elasticsearch
# is enabled, the UUID is derived from the Elasticsearch cluster referenced by output.elasticsearch.
#monitoring.cluster_uuid:

# Uncomment to send the metrics to Elasticsearch. Most settings from the
# Elasticsearch output are accepted here as well.
# Note that the settings should point to your Elasticsearch *monitoring* cluster.
# Any setting that is not set is automatically inherited from the Elasticsearch
# output configuration, so if you have the Elasticsearch output configured such
# that it is pointing to your Elasticsearch monitoring cluster, you can simply
# uncomment the following line.
#monitoring.elasticsearch:

# ============================== Instrumentation ===============================

# Instrumentation support for the filebeat.
#instrumentation:
    # Set to true to enable instrumentation of filebeat.
    #enabled: false

    # Environment in which filebeat is running on (eg: staging, production, etc.)
    #environment: ""

    # APM Server hosts to report instrumentation results to.
    #hosts:
    #  - http://localhost:8200

    # API Key for the APM Server(s).
    # If api_key is set then secret_token will be ignored.
    #api_key:

    # Secret token for the APM Server(s).
    #secret_token:

# ================================= Migration ==================================

# This allows to enable 6.7 migration aliases
#migration.6_to_7.enabled: true

sudo systemctl restart filebeat

# HELK pihole dns conf file
# HELK build Stage: Alpha
# Author: Colin Rubbert (@colinrubbert)
# License: GPL-3.0

input {
  beats {
    port => 5044
  }
}

filter {

  if "pihole" in [tags] {
    grok {
      patterns_dir => ["${LS_HOME}/pipeline/patterns"]
      match => {
        "message" => [

          # request - query type
          "^%{DNSMASQPREFIX} query\[%{DATA:query_type}\] %{FQDN:domain_request} from %{IP:request_from}$",

          # reponse domain to ip
          "^%{DNSMASQPREFIX} reply %{FQDN:domain_request} is %{IP:ip_response}$",

          # response domain is NXDOMAIN
          "^%{DNSMASQPREFIX} reply %{FQDN:domain_request} is NXDOMAIN$",

          # response config domain is NXDOMAIN
          # "^%{DNSMASQPREFIX} config %{FQDN:domain_request} is NXDOMAIN$",

          # response config domain is no - DATA
          # "^%{DNSMASQPREFIX} config %{FQDN:domain_request} is NODATA-IPv[4,6]$",

          # reponse domain to ip cname
          "^%{DNSMASQPREFIX} reply %{FQDN:domain_request} is \<CNAME\>$",

          # respone ip to domain
          "^%{DNSMASQPREFIX} reply %{IP:ip_request} is %{FQDN:domain_response}$",

          # piholed
          # "^%{DNSMASQPREFIX} \/etc\/pihole\/gravity\.list %{FQDN:blocked_domain} is %{IP:pihole}$",

          # piholed 5.0
          "^%{DNSMASQPREFIX} gravity blocked %{FQDN:blocked_domain} is %{IP:pihole}$",

          # piholed local
          # "^%{DNSMASQPREFIX} \/etc\/pihole\/local\.list %{FQDN:blocked_domain} is %{IP:pihole}$",

          # piholed CNAME inspection
          # "^%{DNSMASQPREFIX} reply %{FQDN:domain_request} is blocked during CNAME inspection",

          # blacklist
          # "^%{DNSMASQPREFIX} \/etc\/pihole\/black\.list %{FQDN:blocked_domain} is %{IP:pihole}$",

          # regex
          # "^%{DNSMASQPREFIX} \/etc\/pihole\/regex\.list %{FQDN:blocked_domain} is %{IP:pihole}$",

          # reverse response etc hosts ip to domain
          # "^%{DNSMASQPREFIX} \/etc\/hosts %{IP:ip_request} is %{FQDN:domain_response}$",

          # reverse response etc hosts domain to ip
          # "^%{DNSMASQPREFIX} \/etc\/hosts %{FQDN:domain_request} is %{IP:ip_response}$",

          # forward dns to
          "^%{DNSMASQPREFIX} forwarded %{FQDN:domain_request_forward} to %{IP:dns_forward_to}$",

          # cached domain to ip
          "^%{DNSMASQPREFIX} cached %{FQDN:domain_request} is %{IP:ip_response}$",

          # cached ip to domain
          # "^%{DNSMASQPREFIX} cached %{IP:ip_request} is %{FQDN:domain_response}$",

          # cached is srv
          # "^%{DNSMASQPREFIX} cached %{SRV} is \<SRV\>$",

          # response is srv
          # "^%{DNSMASQPREFIX} reply %{SRV} is \<SRV\>$",

          # cached domain to ip cname
          "^%{DNSMASQPREFIX} cached %{FQDN:domain_request} is \<CNAME\>$",

          # cached domain is NXDOMAIN
          "^%{DNSMASQPREFIX} cached %{FQDN:domain_request} is NXDOMAIN$",

          # cached domain is no - DATA
          "^%{DNSMASQPREFIX} cached %{FQDN:domain_request} is NODATA-IPv[4,6]$",

          # cached domain is no - DATA
          "^%{DNSMASQPREFIX} cached %{FQDN:domain_request} is NODATA$",

          # domain is no - DATA
          "^%{DNSMASQPREFIX} reply %{FQDN:domain_request} is NODATA-IPv[4,6]$",

          # domain is no - DATA
          "^%{DNSMASQPREFIX} reply %{FQDN:domain_request} is NODATA$",

          # exactly blacklisted
          "^%{DNSMASQPREFIX} exactly blacklisted %{FQDN:blocked_domain} is %{IP:pihole}$",

          # regex blacklisted
          "^%{DNSMASQPREFIX} regex blacklisted %{FQDN:blocked_domain} is %{IP:pihole}$",

          # PTR - delete ?
          # "^%{DNSMASQPREFIX} query\[%{WORD:query_type}\] %{HOSTNAMEPTR:request} from %{IP:request_from}$",

          # PTR forwarded - delete ?
          # "^%{DNSMASQPREFIX} forwarded %{HOSTNAMEPTR:request} to %{IP:dns_forward_to}$",

          # clients sending url instead of domain
          # "^%{DNSMASQPREFIX} (query\[.*\]|config|forwarded|reply|cached) %{URI:URI}.*$",

          # SERVFAIL
          "^%{DNSMASQPREFIX} reply error is SERVFAIL"

        ]
      }
    }

    # to do cached and cached reverse

    if [message] =~ "cached"
    and [message] =~ "NXDOMAIN" {
      mutate {
        add_tag => ["cached NXDOMAIN"]
      }
    }

    else if [NODATA] {
      mutate {
        add_tag => ["NODATA"]
      }
    } else if [request_from] and [message] =~ "query" {
      mutate {
        add_tag => ["request and query type"]
      }
    }

    else if [ip_response] and [message] =~ "reply" {
      geoip {
        source => "ip_response"
      }
      mutate {
        add_tag => ["response domain to ip"]
      }
    }

    else if [message] =~ "CNAME"
    and [message] =~ "reply" {
      mutate {
        add_tag => ["response domain to ip CNAME"]
      }
    }

    else if [domain_response] and [message] =~"reply" {
      mutate {
        add_tag => ["response ip to domain"]
      }
      geoip {
        source => "ip_request"
      }
    }

    else if [blocked_domain] {
      mutate {
        add_tag => ["piholed"]
      }
    } else if [message] =~ "\/etc\/hosts" {
      mutate {
        add_tag => ["reverse hostsfile"]
      }
    } else if [dns_forward_to] {
      mutate {
        add_tag => ["dns forward"]
      }
    } else if [ip_request] and [message] =~ "cached" {
      mutate {
        add_tag => ["cached ip to domain"]
      }
      geoip {
        source => "ip_request"
      }
    }

    else if [domain_request] and [message] =~ "cached"
    and [message] =~ "CNAME" {
      mutate {
        add_tag => ["cached domain to ip cname"]
      }
    }

    else if [domain_request] and [message] =~ "cached" {
      mutate {
        add_tag => ["cached domain to ip"]
      }
      geoip {
        source => "ip_response"
      }
    }

    if [domain_request] {
      geoip {
        # cache_size => "10000"
        source => "domain_request"
      }
    }

    if [ip_response] {
      mutate {
        add_field => {
          "ip_or_domain_response" => "%{domain_request}"
        }
      }
    }

    if [domain_response] {
      mutate {
        add_field => {
          "ip_or_domain_response" => "%{domain_response}"
        }
      }
    }

    if [blocked_domain] {
      mutate {
        add_field => {
          "ip_or_domain_response" => "%{blocked_domain}"
        }
      }
    }

    mutate {
      add_field => {
        "[source_fqdn]" => "%{source_host}"
      }
    }

    mutate {
      remove_field => ["port"]
    }

    dns {
      nameserver => "localhost"
      reverse => ["source_fqdn"]
      action => "replace"
      hit_cache_size => 10000
      hit_cache_ttl => 900
      failed_cache_size => 512
      failed_cache_ttl => 900
    }

    date {
      match => ["date", "MMM  d HH:mm:ss", "MMM dd HH:mm:ss"]
      timezone => "America/Chicago"
    }

  }

  if "%" in [source_host] {
    mutate {
      gsub => [
        "source_host", "%.*$", ""
      ]
    }
  }

}

output {
# stdout { codec => rubydebug }
  if "pihole" in [tags]{
    elasticsearch {
      hosts => ["helk-elasticsearch:9200"]
      manage_template => true
      index => "logs-dns-pihole-%{+YYYY.MM.dd}"
      user => 'elastic'
      #password => 'elasticpassword'
    }
  }
}

# From the HELK/docker/helk-logstash/pipeline directory
mkdir patterns

# From the HELK/docker/helk-logstash/pipeline/patterns directory
touch dns-pihole

# dns-pihole pattern
HOSTNAMEPTR \b(?:[\._0-9A-Za-z][0-9A-Za-z-]{0,62})(?:\.(?:[\._0-9A-Za-z][0-9A-Za-z-]{0,62}))*(\.?|\b)
NODATA NODATA-[[:word:]]+
SRV _+.+\S
FQDN \b(?:[\w-][\w-]{0,62})(?:\.(?:[\w-][\w-]{0,62}))*(\.?|\b)
DNSMASQPREFIX %{SYSLOGTIMESTAMP:date} %{SYSLOGPROG}: %{INT:logrow} %{IP:source_host}\/%{POSINT:source_port}
URI %{URIPROTO}:(//)?(?:%{URIHOST})?(?:%{URIPATH})?

# Restart helk-logstash docker container
sudo docker restart helk-logstash