Elasticsearch’s plugin infrastructure is extremely flexible in terms of what can be extended. While it opens up Elasticsearch to a wide variety of (often custom) additional functionality, when it comes to security, this high extensibility level comes at a cost. We have no control over the third-party plugins' code (open source or not) and therefore we cannot guarantee their compliance with Shield. For this reason, third-party plugins are not officially supported on clusters with the Shield security plugin installed.
Elasticsearch clusters with the Shield security plugin installed apply the
/_all wildcard, and all other wildcards,
to the indices that the current user has privileges for, not the set of all indices on the cluster. There are two
notable results of this behavior:
- Elasticsearch clusters with the Shield security plugin installed do not honor the
ignore_unavailableoption. This behavior means that requests involving indices that the current user lacks authorization for throw an
AuthorizationExceptionerror, regardless of the option’s setting.
allow_no_indicesoption is ignored, resulting in the following behavior: when the final set of indices after wildcard expansion and replacement is empty, the request throws a
As a general principle, core Elasticsearch will return empty results in scenarios where wildcard expansion returns no indices, while Elasticsearch with Shield returns exceptions. Note that this behavior means that operations with multiple items will fail the entire set of operations if any one operation throws an exception due to wildcard expansion resulting in an empty set of authorized indices.
You can combine a secured index alias with a filter to approximate document-level security. By manipulating the specific filtering, you can control the set of documents that users with privileges on that index alias can access.
Filtering secured index aliases does not provide security for documents retrieved through the
get api. Read
Elasticsearch issue #3861 to learn more about this limitation.
Users can obtain secure near-real-time get under this restriction with searches by document ID, using the
search api instead. Restrict get operations when you use this approach by granting the
privilege and disallowing
In Elasticsearch, issuing a delete operation on an alias also deletes all of the indices that the alias points to, regardless of the filter that the alias might hold. Keep this behavior in mind when granting users administrative privileges to filtered index aliases. Read Elasticsearch issue #2318 to learn more about this limitation.
A filtered index alias will not provide document-level security for the suggesters apis as they do not take into account the filters placed on aliases.
A filtered index alias will not provide document-level security when using a Children Aggregation as the filter from the alias is not used when computing the aggregation results.
Elasticsearch 1.6 removes all of the limitations below with queries and filters with the exception of the More Like This Query.
But there is the possibility of authorization being bypassed when using a terms filter with the
terms lookup mechanism. The authorization that could be
bypassed is for the index containing the terms when using Shield 1.2.0 and 1.2.1. If using Shield 1.2.0 or 1.2.1,
add the following setting to your
elasticsearch.yml file to ensure that requests are properly authorized:
Shield 1.2.2+ does not require this setting to be specified.
Elasticsearch 1.6.2+ and 1.7.1+ remove the limitations on the More Like This Query.
Certain Elasticsearch requests execute other requests as part of their implementation. Some of these requests do not
maintain the security context that the original request was made with. This causes an
AuthorizationException even when
the user has authorization to make the subsequent requests. The following requests have this behavior:
Document expiration handled using the built-in
_ttl (time to live) mechanism
does not work with Shield. The document deletions will fail and the documents continue to live past their expiration.
The LDAP Realm does not currently support the discovery of nested LDAP Groups. For example, if a user is a member of GroupA and GroupA is a member of GroupB, only GroupA will be discovered. However, the Active Directory Realm does support transitive group membership.