[system.auth] redundant regex operation warning in Elasticsearch

[fdartayre]

A grok processor from the logs-system.auth-1.19.3 ingestion pipeline causes the following warning in Elasticsearch logs:

regular expression has redundant nested repeat operator * /^(?<TIMESTAMP:system.auth.timestamp>(?:(?:(?:(?>\d\d){1,2})-(?:(?:0?[1-9]|1[0-2]))-(?:(?:(?:0[1-9])|(?:[12][0-9])|(?:3[01])|[1-9]))[T ](?:(?:2[0123]|[01][0-9])):?(?:(?:[0-5][0-9]))(?::?(?:(?:(?:[0-5]?[0-9]|60)(?:[:.,][0-9]+)?)))?(?:(?:Z|[+-](?:(?:2[0123]|[01]?[0-9]))(?::?(?:(?:[0-5][0-9])))))?)|(?:(?:\b(?:[Jj]an(?:uary|uar)?|[Ff]eb(?:ruary|ruar)?|[Mm](?:a|ä)?r(?:ch|z)?|[Aa]pr(?:il)?|[Mm]a(?:y|i)?|[Jj]un(?:e|i)?|[Jj]ul(?:y|i)?|[Aa]ug(?:ust)?|[Ss]ep(?:tember)?|[Oo](?:c|k)?t(?:ober)?|[Nn]ov(?:ember)?|[Dd]e(?:c|z)(?:ember)?)\b) +(?:(?:(?:0[1-9])|(?:[12][0-9])|(?:3[01])|[1-9])) (?:(?!<[0-9])(?:(?:2[0123]|[01]?[0-9])):(?:(?:[0-5][0-9]))(?::(?:(?:(?:[0-5]?[0-9]|60)(?:[:.,][0-9]+)?)))(?![0-9]))))) (?<SYSLOGHOST:host.hostname>(?:(?:(?:(?:(?:((([0-9A-Fa-f]{1,4}:){7}([0-9A-Fa-f]{1,4}|:))|(([0-9A-Fa-f]{1,4}:){6}(:[0-9A-Fa-f]{1,4}|((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3})|((:[0-9A-Fa-f]{1,4})?:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){1,4})|((:[0-9A-Fa-f]{1,4}){0,2}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5})|((:[0-9A-Fa-f]{1,4}){0,3}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){1,6})|((:[0-9A-Fa-f]{1,4}){0,4}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(:(((:[0-9A-Fa-f]{1,4}){1,7})|((:[0-9A-Fa-f]{1,4}){0,5}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:)))(%.+)?)|(?:(?<![0-9])(?:(?:[0-1]?[0-9]{1,2}|2[0-4][0-9]|25[0-5])[.](?:[0-1]?[0-9]{1,2}|2[0-4][0-9]|25[0-5])[.](?:[0-1]?[0-9]{1,2}|2[0-4][0-9]|25[0-5])[.](?:[0-1]?[0-9]{1,2}|2[0-4][0-9]|25[0-5]))(?![0-9]))))|(?:\b(?:[0-9A-Za-z][0-9A-Za-z-]{0,62})(?:\.(?:[0-9A-Za-z][0-9A-Za-z-]{0,62}))*(\.?|\b)))))? (?<DATA:[process.name](https://process.name/)>.*?)(?:\[(?<POSINT:process.pid:long>\b(?:[1-9][0-9]*)\b)\])?:(?:\s*)+(?<GREEDYMULTILINE:_temp.message>(.|\n)*)$/

[elasticmachine]

Pinging @elastic/integrations (Team:Integrations)

[botelastic]

Hi! We just realized that we haven't looked into this issue in a while. We're sorry! We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1. Thank you for your contribution!

[elasticmachine]

Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

[efd6]

This comes from the header grok in the pipeline preamble.

  - grok:
      description: Grok the message header.
      tag: grok-message-header
      field: event.original
      pattern_definitions:
        GREEDYMULTILINE: '(.|\n)*'
        TIMESTAMP: (?:%{TIMESTAMP_ISO8601}|%{SYSLOGTIMESTAMP})
      patterns:
        - '^%{TIMESTAMP:system.auth.timestamp} %{SYSLOGHOST:host.hostname}? %{DATA:process.name}(?:\[%{POSINT:process.pid:long}\])?:%{SPACE}%{GREEDYMULTILINE:_temp.message}$'

The only instance of a redundant Kleene star is in (?:\s*)+, but that is specified in the definitions as %{SPACE}.

This issue was fixed in #5320.

This redundant pattern definition does exist in other integrations.

$ rg '%\{SPACE\}\+'
packages/cisco_ftd/data_stream/log/elasticsearch/ingest_pipeline/default.yml
351:      - "AAA user %{DATA:_temp_.cisco.aaa_type} Successful(%{SPACE})?: server =(%{SPACE}+)?%{IP:destination.address} [:,] [Uu]ser = %{CISCO_USER:source.user.name}"

packages/cisco_asa/data_stream/log/elasticsearch/ingest_pipeline/default.yml
448:      - "AAA user %{DATA:_temp_.cisco.aaa_type} Successful(%{SPACE})?: server =(%{SPACE}+)?%{IP:destination.address} [:,] [Uu]ser = %{CISCO_USER:source.user.name}"

packages/juniper_srx/data_stream/log/elasticsearch/ingest_pipeline/default.yml
24:        CUSTOM_DATE: "%{TIMESTAMP_ISO8601}|(%{MONTH}%{SPACE}+%{MONTHDAY}%{SPACE}+%{TIME})"