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2021-08-06 10:35:01 +02:00

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filter {
# todo: make added fields not zeek-specific? (see ECS topic branch)
# all the lookups are done here, but some of them are still zeek-specific which
# IMO isn't the cleanest. could be refactored/split.
######## MAC address OUI (manufacturer) lookup #################################################
# if OUI lookup is requested, enable it
mutate {
id => "mutate_add_field_env_logstash_oui_lookup"
add_field => { "[@metadata][ENV_LOGSTASH_OUI_LOOKUP]" => "${LOGSTASH_OUI_LOOKUP:false}" }
}
if ([@metadata][ENV_LOGSTASH_OUI_LOOKUP] == "true") {
# srcMac/dstMac are arrays at this point, as Arkime expects them to be
if ([srcMac]) and ([srcMac][0]) {
# attempt lookup of srcMac oui
ieee_oui {
id => "ieee_oui_srcMac"
source => "[srcMac][0]"
target => "[zeek][orig_l2_oui]"
ouifile => "/usr/share/logstash/config/oui-logstash.txt"
refresh_interval => 0
}
if ([zeek][orig_l2_oui]) {
# merge orig_l2_oui into srcOui array (with a count of 1)
mutate { id => "mutate_merge_field_srcOui"
merge => { "[srcOui]" => "[zeek][orig_l2_oui]" } }
mutate { id => "mutate_add_field_srcOuiCnt"
add_field => { "[srcOuiCnt]" => "1" } }
# if this is a DHCP log type, copy srcOui to dhcp.oui
if ([dhcp][mac]) {
mutate {
id => "mutate_add_fields_dhcp_oui"
add_field => { "[dhcp][oui]" => "%{[srcOui]}" }
}
mutate {
id => "mutate_add_fields_dhcp_ouiCnt"
add_field => { "[dhcp][ouiCnt]" => "%{[srcOuiCnt]}" }
}
}
}
} # end if [srcMac]
if ([dstMac]) and ([dstMac][0]) {
# attempt lookup of dstMac oui
ieee_oui {
id => "ieee_oui_dstMac"
source => "[dstMac][0]"
target => "[zeek][resp_l2_oui]"
ouifile => "/usr/share/logstash/config/oui-logstash.txt"
refresh_interval => 0
}
if ([zeek][resp_l2_oui]) {
# merge resp_l2_oui into dstOui array (with a count of 1)
mutate { id => "mutate_merge_field_dstOui"
merge => { "[dstOui]" => "[zeek][resp_l2_oui]" } }
mutate { id => "mutate_add_field_dstOuiCnt"
add_field => { "[dstOuiCnt]" => "1" } }
}
} # end if [dstMac]
} # end if ENV_LOGSTASH_OUI_LOOKUP
################################################################################################
######## IP address class tagging, GeoIP/ASN lookups, and reverse DNS ###########################
if ([srcIp]) {
cidr {
id => "cidr_add_tag_internal_source"
add_tag => [ "internal_source" ]
address => [ "%{srcIp}" ]
network => [ "0.0.0.0/8", "10.0.0.0/8", "100.64.0.0/10", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24", "192.0.2.0/24",
"192.88.99.0/24", "192.168.0.0/16", "198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "224.0.0.0/4", "240.0.0.0/4",
"255.255.255.255/32", "::/0", "::/128", "::1/128", "fc00::/7", "fe80::/10", "ff00::/8"]
}
if (!("internal_source" in [tags])) {
mutate { id => "mutate_add_tag_external_source"
add_tag => [ "external_source" ] }
# map srcIp to GEO countries
geoip {
id => "geoip_srcIp_geo"
source => "[srcIp]"
target => "[zeek][source_geo]"
}
geoip {
id => "geoip_srcIp_asn"
default_database_type => "ASN"
source => "[srcIp]"
target => "[@metadata][orig_asn]"
}
if ([zeek][source_geo] and [zeek][source_geo][country_code2]) {
mutate { id => "mutate_add_field_srcGEO"
add_field => { "[srcGEO]" => "%{[zeek][source_geo][country_code2]}" } }
}
if ([@metadata][orig_asn] and [@metadata][orig_asn][as_org] and [@metadata][orig_asn][asn]) {
mutate { id => "mutate_add_field_srcASN"
add_field => { "[srcASN]" => "AS%{[@metadata][orig_asn][asn]} %{[@metadata][orig_asn][as_org]}" } }
}
# if reverse DNS for public IP addresses is enabled (via environment variable) do it
mutate {
add_field => { "[@metadata][ENV_LOGSTASH_REVERSE_DNS]" => "${LOGSTASH_REVERSE_DNS:false}" }
}
if ([@metadata][ENV_LOGSTASH_REVERSE_DNS] == "true") {
mutate {
id => "mutate_add_field_srcip_for_dns"
add_field => {
"[zeek][source_ip_reverse_dns]" => "%{[srcIp]}"
}
}
dns {
id => "dns_source_ip_reverse_dns"
reverse => [ "[zeek][source_ip_reverse_dns]" ]
action => "replace"
hit_cache_size => 8000
hit_cache_ttl => 300
failed_cache_size => 8000
failed_cache_ttl => 60
}
if ([srcIp] == [zeek][source_ip_reverse_dns]) {
mutate {
id => "mutate_remove_field_source_ip_reverse_dns"
remove_field => [ "[zeek][source_ip_reverse_dns]" ]
}
}
}
}
cidr {
id => "cidr_detect_network_type_ipv4_source"
add_field => { "[network][type]" => "ipv4" }
address => [ "%{srcIp}" ]
network => [ "0.0.0.0/0" ]
}
if (![network][type]) {
mutate { id => "mutate_add_network_type_ipv4_source"
add_field => { "[network][type]" => "ipv6" } }
}
} # if ([srcIp])
if ([dstIp]) {
cidr {
id => "cidr_add_tag_internal_destination"
add_tag => [ "internal_destination" ]
address => [ "%{dstIp}" ]
network => [ "0.0.0.0/8", "10.0.0.0/8", "100.64.0.0/10", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24", "192.0.2.0/24",
"192.88.99.0/24", "192.168.0.0/16", "198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "224.0.0.0/4", "240.0.0.0/4",
"255.255.255.255/32", "::/0", "::/128", "::1/128", "fc00::/7", "fe80::/10", "ff00::/8"]
}
if (!("internal_destination" in [tags])) {
mutate { id => "mutate_add_tag_external_destination"
add_tag => [ "external_destination" ] }
# map dstIp to GEO countries
geoip {
id => "geoip_dstIp_geo"
source => "[dstIp]"
target => "[zeek][destination_geo]"
}
geoip {
id => "geoip_dstIp_asn"
default_database_type => "ASN"
source => "[dstIp]"
target => "[@metadata][resp_asn]"
}
if ([zeek][destination_geo] and [zeek][destination_geo][country_code2]) {
mutate { id => "mutate_add_field_dstGEO"
add_field => { "[dstGEO]" => "%{[zeek][destination_geo][country_code2]}" } }
}
if ([@metadata][resp_asn] and [@metadata][resp_asn][as_org] and [@metadata][resp_asn][asn]) {
mutate { id => "mutate_add_field_dstASN"
add_field => { "[dstASN]" => "AS%{[@metadata][resp_asn][asn]} %{[@metadata][resp_asn][as_org]}" } }
}
# if reverse DNS for public IP addresses is enabled (via environment variable) do it
if (![@metadata][ENV_LOGSTASH_REVERSE_DNS]) {
mutate {
add_field => { "[@metadata][ENV_LOGSTASH_REVERSE_DNS]" => "${LOGSTASH_REVERSE_DNS:false}" }
}
}
if ([@metadata][ENV_LOGSTASH_REVERSE_DNS] == "true") {
mutate {
id => "mutate_add_field_dstip_for_dns"
add_field => {
"[zeek][destination_ip_reverse_dns]" => "%{[dstIp]}"
}
}
dns {
id => "dns_destination_ip_reverse_dns"
reverse => [ "[zeek][destination_ip_reverse_dns]" ]
action => "replace"
hit_cache_size => 8000
hit_cache_ttl => 300
failed_cache_size => 8000
failed_cache_ttl => 60
}
if ([dstIp] == [zeek][destination_ip_reverse_dns]) {
mutate {
id => "mutate_remove_field_destination_ip_reverse_dns"
remove_field => [ "[zeek][destination_ip_reverse_dns]" ]
}
}
}
}
if (![network][type]) {
cidr {
id => "cidr_detect_network_type_ipv4_dest"
add_field => { "[network][type]" => "ipv4" }
address => [ "%{dstIp}" ]
network => [ "0.0.0.0/0" ]
}
if (![network][type]) {
mutate { id => "mutate_add_network_type_ipv4_dest"
add_field => { "[network][type]" => "ipv6" } }
}
}
} # if ([dstIp])
if ([dns][host]) {
# if requested, look up DNS queries using freq_server.py to get entropy scores
ruby {
id => "ruby_dns_freq_lookup"
init => "
require 'net/http'
require 'cgi'
$freqLookupEnabled = ENV['FREQ_LOOKUP'] || 'false'
"
# freq_server.py returns a string like: (2.9333, 3.6353)
code => "
if ($freqLookupEnabled == 'true') then
scoresv1 = Array.new
scoresv2 = Array.new
scoresTmp = Array.new
begin
event.get('[dns][host]').each { |query|
if (query.length >= 4) and (query !~ /(ip6\.int|ip6\.arpa|in-addr\.arpa|b32\.i2p)$/i) then
scoresTmp.clear
scoresTmp.concat(Net::HTTP.get_response(URI.parse('http://freq:10004/measure/' + CGI.escape(query))).body.gsub(/(^\(|\)$|\s+)/, '').split(',').map(&:to_f))
if (scoresTmp.length == 2) then
scoresv1 << scoresTmp[0]
scoresv2 << scoresTmp[1]
end
end
}
rescue Exception => e
event.set('ruby_exception', 'ruby_dns_freq_lookup: ' + e.message)
end
event.set('[zeek][freq_score_v1]', scoresv1) unless (scoresv1.length == 0)
event.set('[zeek][freq_score_v2]', scoresv2) unless (scoresv2.length == 0)
end"
}
} # end if dns.ip
if ([dns][ip]) and ([dns][ip][0]) {
# if this is a DNS record with an IP, GeoIP it as well
geoip {
id => "geoip_dns_ip_asn"
default_database_type => "ASN"
source => "[dns][ip][0]"
target => "[@metadata][dns_asn]"
}
if ([@metadata][dns_asn] and [@metadata][dns_asn][as_org] and [@metadata][dns_asn][asn]) {
# this is stupid, the %{} doesn't seem to be liked by mutate.merge
mutate { id => "mutate_add_field_dns_asn"
add_field => { "[@metadata][asn_str]" => "AS%{[@metadata][dns_asn][asn]} %{[@metadata][dns_asn][as_org]}" } }
mutate { id => "mutate_merge_dns_asn"
merge => { "[dns][ASN]" => "[@metadata][asn_str]" } }
}
geoip {
id => "geoip_dns_ip_geo"
source => "[dns][ip][0]"
target => "[@metadata][dns_geo]"
}
if ([@metadata][dns_geo] and [@metadata][dns_geo][country_code2]) {
mutate { id => "mutate_merge_dns_geo"
merge => { "[dns][GEO]" => "[@metadata][dns_geo][country_code2]" } }
}
} # end if dns.ip
if ([radius]) {
# if this is a Radius record with IP addresses, GeoIP them as well
if ([radius][framedIp]) and ([radius][framedIp][0]) {
geoip {
id => "geoip_radius_framedIp_asn"
default_database_type => "ASN"
source => "[radius][framedIp][0]"
target => "[@metadata][radius_asn]"
}
if ([@metadata][radius_asn] and [@metadata][radius_asn][as_org] and [@metadata][radius_asn][asn]) {
# this is stupid, the %{} doesn't seem to be liked by mutate.merge
mutate { id => "mutate_add_field_radius_asn"
add_field => { "[@metadata][asn_str]" => "AS%{[@metadata][radius_asn][asn]} %{[@metadata][radius_asn][as_org]}" } }
mutate { id => "mutate_merge_radius_asn"
merge => { "[radius][framedASN]" => "[@metadata][asn_str]" } }
}
geoip {
id => "geoip_radius_framedIp_geo"
source => "[radius][framedIp][0]"
target => "[@metadata][radius_geo]"
}
if ([@metadata][radius_geo] and [@metadata][radius_geo][country_code2]) {
mutate { id => "mutate_merge_radius_geo"
merge => { "[radius][framedGEO]" => "[@metadata][radius_geo][country_code2]" } }
}
} # end if radius.framedIp
if ([radius][endpointIp]) and ([radius][endpointIp][0]) {
geoip {
id => "geoip_radius_endpointIp_asn"
default_database_type => "ASN"
source => "[radius][endpointIp][0]"
target => "[@metadata][radius_asn]"
}
if ([@metadata][radius_asn] and [@metadata][radius_asn][as_org] and [@metadata][radius_asn][asn]) {
# this is stupid, the %{} doesn't seem to be liked by mutate.merge
mutate { id => "mutate_add_field_radius_endpoint_asn"
add_field => { "[@metadata][asn_str]" => "AS%{[@metadata][radius_asn][asn]} %{[@metadata][radius_asn][as_org]}" } }
mutate { id => "mutate_merge_radius_endpoint_asn"
merge => { "[radius][endpointASN]" => "[@metadata][asn_str]" } }
}
geoip {
id => "geoip_radius_endpointIp_geo"
source => "[radius][endpointIp][0]"
target => "[@metadata][radius_geo]"
}
if ([@metadata][radius_geo] and [@metadata][radius_geo][country_code2]) {
mutate { id => "mutate_merge_radius_endpoint_geo"
merge => { "[radius][endpointGEO]" => "[@metadata][radius_geo][country_code2]" } }
}
} # end if radius.endpointIp
} # end if radius
if ([zeek_cip_identity][socket_address]) {
# if this is a zeek_cip_identity record with socket_address, ASN/GeoIP it as well
geoip {
id => "geoip_zeek_cip_identity_socket_address"
default_database_type => "ASN"
source => "[zeek_cip_identity][socket_address]"
target => "[@metadata][zeek_cip_identity_asn]"
}
if ([@metadata][zeek_cip_identity_asn] and [@metadata][zeek_cip_identity_asn][as_org] and [@metadata][zeek_cip_identity_asn][asn]) {
# this is stupid, the %{} doesn't seem to be liked by mutate.merge
mutate { id => "mutate_add_field_zeek_cip_identity_asn"
add_field => { "[@metadata][cip_asn_str]" => "AS%{[@metadata][zeek_cip_identity_asn][asn]} %{[@metadata][zeek_cip_identity_asn][as_org]}" } }
mutate { id => "mutate_merge_zeek_cip_identity_asn"
merge => { "[zeek_cip_identity][socket_address_asn]" => "[@metadata][cip_asn_str]" } }
}
geoip {
id => "geoip_zeek_cip_identity_socket_address_geo"
source => "[zeek_cip_identity][socket_address]"
target => "[zeek_cip_identity][socket_address_geo]"
}
} # end if zeek_cip_identity.socket_address
if ([zeek_ssl][server_name]) {
mutate {
add_field => { "[@metadata][ENV_FREQ_LOOKUP]" => "${FREQ_LOOKUP:false}" }
}
if ([@metadata][ENV_FREQ_LOOKUP] == "true") {
# if requested, look up zeek_ssl.server_name queries using freq_server.py to get entropy scores
http {
id => "rest_zeek_ssl_server_name_freq_lookup"
url => "http://freq:10004/measure/%{[zeek_ssl][server_name]}"
target_body => "[@metadata][zeek_ssl_server_name_freq]"
}
if ([@metadata][zeek_ssl_server_name_freq]) {
grok {
id => "grok_zeek_ssl_server_name_freq_parse"
match => { "[@metadata][zeek_ssl_server_name_freq]" => [ "^\(%{NUMBER:[zeek][freq_score_v1]}, %{NUMBER:[zeek][freq_score_v2]}\)$" ] }
}
}
}
} # end if zeek_ssl.server_name
################################################################################################
######## JA3 community hashes lookup ###########################################################
# ja3/ja3s are arrays at this point, as Arkime expects them to be
if ([tls][ja3]) and ([tls][ja3][0]) {
translate {
id => "translate_ssl_ja3"
field => "[tls][ja3][0]"
destination => "[zeek_ssl][ja3_desc]"
dictionary_path => "/etc/ja3.yaml"
}
}
if ([tls][ja3s]) and ([tls][ja3s][0]) {
translate {
id => "translate_ssl_ja3s"
field => "[tls][ja3s][0]"
destination => "[zeek_ssl][ja3s_desc]"
dictionary_path => "/etc/ja3.yaml"
}
}
################################################################################################
# this identifies which node the log came from
if ([host][name]) {
mutate { id => "mutate_add_field_host_name_node"
add_field => { "[node]" => "%{[host][name]}" } }
} else {
mutate { id => "mutate_add_field_logstash_node"
add_field => { "[node]" => "logs" } }
}
if ([log][file][path]) {
# trim path portion of log.file.path
mutate { id => "mutate_gsub_field_zeek_log_file_path"
gsub => [ "[log][file][path]", "^.*/", "" ] }
}
# remove some useless beats-related fields
mutate {
id => "mutate_remove_field_beats_useless"
remove_field => [
"[beat]",
"[agent][ephemeral_id]",
"[log][offset]",
"[input][type]",
"[prospector]",
"[message]"
]
}
} # end Filter