A permission issue was found in Elasticsearch versions before 5.6.15 and 6.6.1 when Field Level Security and Document Level Security are disabled and the _aliases, _shrink, or _split endpoints are used . If the elasticsearch.yml file has xpack.security.dls_fls.enabled set to false, certain permission checks are skipped when users perform one of the actions mentioned above, to make existing data available under a new index/alias name. This could result in an attacker gaining additional permissions against a restricted index.

References

• https://nvd.nist.gov/vuln/detail/CVE-2019-7611
• https://discuss.elastic.co/t/elastic-stack-6-6-1-and-5-6-15-security-update/169077
• https://www.elastic.co/community/security