[role="xpack"]
[testenv="basic"]
[[eql-search]]
== Run an EQL search

experimental::[]

To start using EQL in {es}, first ensure your event data meets
<<eql-requirements,EQL requirements>>. Then ingest or add the data to an {es}
index.

The following <<docs-bulk,bulk API>> request adds some example log data to the
`sec_logs` index. This log data follows the {ecs-ref}[Elastic Common Schema
(ECS)].

[source,console]
----
PUT sec_logs/_bulk?refresh
{"index":{"_index" : "sec_logs", "_id" : "1"}}
{ "@timestamp": "2020-12-06T11:04:05.000Z", "agent": { "id": "8a4f500d" }, "event": { "category": "process" }, "process": { "name": "cmd.exe", "path": "C:\\Windows\\System32\\cmd.exe" } }
{"index":{"_index" : "sec_logs", "_id" : "2"}}
{ "@timestamp": "2020-12-06T11:04:07.000Z", "agent": { "id": "8a4f500d" }, "event": { "category": "file" }, "file": { "accessed": "2020-12-07T11:07:08.000Z", "name": "cmd.exe", "path": "C:\\Windows\\System32\\cmd.exe", "type": "file", "size": 16384 }, "process": { "name": "cmd.exe", "path": "C:\\Windows\\System32\\cmd.exe" } }
{"index":{"_index" : "sec_logs", "_id" : "3"}}
{ "@timestamp": "2020-12-07T11:06:07.000Z", "agent": { "id": "8a4f500d" }, "event": { "category": "process" }, "process": { "name": "cmd.exe", "path": "C:\\Windows\\System32\\cmd.exe" } }
{"index":{"_index" : "sec_logs", "_id" : "4"}}
{ "@timestamp": "2020-12-07T11:07:08.000Z", "agent": { "id": "8a4f500d" }, "event": { "category": "file" }, "file": { "accessed": "2020-12-07T11:07:08.000Z", "name": "cmd.exe", "path": "C:\\Windows\\System32\\cmd.exe", "type": "file", "size": 16384 }, "process": { "name": "cmd.exe", "path": "C:\\Windows\\System32\\cmd.exe" } }
{"index":{"_index" : "sec_logs", "_id" : "5"}}
{ "@timestamp": "2020-12-07T11:07:09.000Z", "agent": { "id": "8a4f500d" }, "event": { "category": "process" }, "process": { "name": "regsvr32.exe", "path": "C:\\Windows\\System32\\regsvr32.exe" } }
----
// TESTSETUP

You can now use the EQL search API to search this index using an EQL query.

The following request searches the `sec_logs` index using the EQL query
specified in the `query` parameter. The EQL query matches events with an
`event.category` of `process` that have a `process.name` of `cmd.exe`.

[source,console]
----
GET sec_logs/_eql/search
{
  "query": """
    process where process.name == "cmd.exe"
  """
}
----

Because the `sec_log` index follows the ECS, you don't need to specify the
required <<eql-required-fields,event category or timestamp>> fields. The request
uses the `event.category` and `@timestamp` fields by default.

The API returns the following response containing the matching events. Events
in the response are sorted by timestamp, converted to milliseconds since the
https://en.wikipedia.org/wiki/Unix_time[Unix epoch], in ascending order.

[source,console-result]
----
{
  "took": 60,
  "timed_out": false,
  "hits": {
    "total": {
      "value": 2,
      "relation": "eq"
    },
    "events": [
      {
        "_index": "sec_logs",
        "_type": "_doc",
        "_id": "1",
        "_score": null,
        "_source": {
          "@timestamp": "2020-12-06T11:04:05.000Z",
          "agent": {
            "id": "8a4f500d"
          },
          "event": {
            "category": "process"
          },
          "process": {
            "name": "cmd.exe",
            "path": "C:\\Windows\\System32\\cmd.exe"
          }
        },
        "sort": [
          1607252645000
        ]
      },
      {
        "_index": "sec_logs",
        "_type": "_doc",
        "_id": "3",
        "_score": null,
        "_source": {
          "@timestamp": "2020-12-07T11:06:07.000Z",
          "agent": {
            "id": "8a4f500d"
          },
          "event": {
            "category": "process"
          },
          "process": {
            "name": "cmd.exe",
            "path": "C:\\Windows\\System32\\cmd.exe"
          }
        },
        "sort": [
          1607339167000
        ]
      }
    ]
  }
}
----
// TESTRESPONSE[s/"took": 60/"took": $body.took/]

[discrete]
[[eql-search-specify-event-category-field]]
=== Specify an event category field

The EQL search API uses `event.category` as the required
<<eql-required-fields,event category field>> by default. You can use the
`event_category_field` parameter to specify another event category field.

For example, the following request specifies `file.type` as the event category
field.

[source,console]
----
GET sec_logs/_eql/search
{
   "event_category_field": "file.type",
  "query": """
    file where agent.id == "8a4f500d"
  """
}
----

[discrete]
[[eql-search-specify-timestamp-field]]
=== Specify a timestamp field

The EQL search API uses `@timestamp` as the required <<eql-required-fields,event
timestamp field>> by default. You can use the `timestamp_field` parameter to
specify another timestamp field.

For example, the following request specifies `file.accessed` as the event
timestamp field.

[source,console]
----
GET sec_logs/_eql/search
{
  "timestamp_field": "file.accessed",
  "query": """
    file where (file.size > 1 and file.type == "file")
  """
}
----

[discrete]
[[eql-search-filter-query-dsl]]
=== Filter using query DSL

You can use the `filter` parameter to specify an additional query using
<<query-dsl,query DSL>>. This query filters the documents on which the EQL query
runs.

For example, the following request uses a `range` query to filter the `sec_logs`
index down to only documents with a `file.size` value greater than `1` but less
than `1000000` bytes. The EQL query in `query` parameter then runs on these
filtered documents.

[source,console]
----
GET sec_logs/_eql/search
{
  "filter": {
    "range" : {
      "file.size" : {
        "gte" : 1,
        "lte" : 1000000
      }
    }
  },
  "query": """
    file where (file.type == "file" and file.name == "cmd.exe")
  """
}
----