EQL search
editEQL search
editEvent Query Language (EQL) is a query language for event-based time series data, such as logs, metrics, and traces.
Advantages of EQL
edit-
EQL lets you express relationships between events.
Many query languages allow you to match single events. EQL lets you match a sequence of events across different event categories and time spans. -
EQL has a low learning curve.
EQL syntax looks like other common query languages, such as SQL. EQL lets you write and read queries intuitively, which makes for quick, iterative searching. -
EQL is designed for security use cases.
While you can use it for any event-based data, we created EQL for threat hunting. EQL not only supports indicator of compromise (IOC) searches but can describe activity that goes beyond IOCs.
Required fields
editTo run an EQL search, the searched data stream or index must contain a
timestamp and event category field. By default, EQL uses the @timestamp
and event.category
fields from the Elastic Common Schema
(ECS). To use a different timestamp or event category field, see
Specify a timestamp or event category field.
While no schema is required to use EQL, we recommend using the ECS. EQL searches are designed to work with core ECS fields by default.
Run an EQL search
editUse the EQL search API to run a basic EQL query.
GET /my-data-stream/_eql/search { "query": """ process where process.name == "regsvr32.exe" """ }
By default, basic EQL queries return the 10 most recent matching events in the
hits.events
property. These hits are sorted by timestamp, converted to
milliseconds since the Unix epoch, in ascending order.
{ "is_partial": false, "is_running": false, "took": 60, "timed_out": false, "hits": { "total": { "value": 2, "relation": "eq" }, "events": [ { "_index": ".ds-my-data-stream-2099.12.07-000001", "_id": "OQmfCaduce8zoHT93o4H", "_source": { "@timestamp": "2099-12-07T11:07:09.000Z", "event": { "category": "process", "id": "aR3NWVOs", "sequence": 4 }, "process": { "pid": 2012, "name": "regsvr32.exe", "command_line": "regsvr32.exe /s /u /i:https://...RegSvr32.sct scrobj.dll", "executable": "C:\\Windows\\System32\\regsvr32.exe" } } }, { "_index": ".ds-my-data-stream-2099.12.07-000001", "_id": "xLkCaj4EujzdNSxfYLbO", "_source": { "@timestamp": "2099-12-07T11:07:10.000Z", "event": { "category": "process", "id": "GTSmSqgz0U", "sequence": 6, "type": "termination" }, "process": { "pid": 2012, "name": "regsvr32.exe", "executable": "C:\\Windows\\System32\\regsvr32.exe" } } } ] } }
Use the size
parameter to get a smaller or larger set of hits:
GET /my-data-stream/_eql/search { "query": """ process where process.name == "regsvr32.exe" """, "size": 50 }
Search for a sequence of events
editUse EQL’s sequence syntax to search for a series of ordered events. List the event items in ascending chronological order, with the most recent event listed last:
GET /my-data-stream/_eql/search { "query": """ sequence [ process where process.name == "regsvr32.exe" ] [ file where stringContains(file.name, "scrobj.dll") ] """ }
The response’s hits.sequences
property contains the 10 most recent matching
sequences.
{ ... "hits": { "total": ..., "sequences": [ { "events": [ { "_index": ".ds-my-data-stream-2099.12.07-000001", "_id": "OQmfCaduce8zoHT93o4H", "_source": { "@timestamp": "2099-12-07T11:07:09.000Z", "event": { "category": "process", "id": "aR3NWVOs", "sequence": 4 }, "process": { "pid": 2012, "name": "regsvr32.exe", "command_line": "regsvr32.exe /s /u /i:https://...RegSvr32.sct scrobj.dll", "executable": "C:\\Windows\\System32\\regsvr32.exe" } } }, { "_index": ".ds-my-data-stream-2099.12.07-000001", "_id": "yDwnGIJouOYGBzP0ZE9n", "_source": { "@timestamp": "2099-12-07T11:07:10.000Z", "event": { "category": "file", "id": "tZ1NWVOs", "sequence": 5 }, "process": { "pid": 2012, "name": "regsvr32.exe", "executable": "C:\\Windows\\System32\\regsvr32.exe" }, "file": { "path": "C:\\Windows\\System32\\scrobj.dll", "name": "scrobj.dll" } } } ] } ] } }
Use with maxspan
to constrain matching sequences
to a timespan:
GET /my-data-stream/_eql/search { "query": """ sequence with maxspan=1h [ process where process.name == "regsvr32.exe" ] [ file where stringContains(file.name, "scrobj.dll") ] """ }
Use the by
keyword to match events that share the
same field values:
GET /my-data-stream/_eql/search { "query": """ sequence with maxspan=1h [ process where process.name == "regsvr32.exe" ] by process.pid [ file where stringContains(file.name, "scrobj.dll") ] by process.pid """ }
If a field value should be shared across all events, use the sequence by
keyword. The following query is equivalent to the previous one.
GET /my-data-stream/_eql/search { "query": """ sequence by process.pid with maxspan=1h [ process where process.name == "regsvr32.exe" ] [ file where stringContains(file.name, "scrobj.dll") ] """ }
The hits.sequences.join_keys
property contains the shared field values.
{ ... "hits": ..., "sequences": [ { "join_keys": [ 2012 ], "events": ... } ] } }
Use the until
keyword to specify an expiration
event for sequences. Matching sequences must end before this event.
GET /my-data-stream/_eql/search { "query": """ sequence by process.pid with maxspan=1h [ process where process.name == "regsvr32.exe" ] [ file where stringContains(file.name, "scrobj.dll") ] until [ process where event.type == "termination" ] """ }
Retrieve selected fields
editBy default, each hit in the search response includes the document _source
,
which is the entire JSON object that was provided when indexing the document.
You can use the filter_path
query
parameter to filter the API response. For example, the following search returns
only the timestamp and PID from the _source
of each matching event.
GET /my-data-stream/_eql/search?filter_path=hits.events._source.@timestamp,hits.events._source.process.pid { "query": """ process where process.name == "regsvr32.exe" """ }
The API returns the following response.
{ "hits": { "events": [ { "_source": { "@timestamp": "2099-12-07T11:07:09.000Z", "process": { "pid": 2012 } } }, { "_source": { "@timestamp": "2099-12-07T11:07:10.000Z", "process": { "pid": 2012 } } } ] } }
You can also use the fields
parameter to retrieve and format specific fields
in the response. This field is identical to the search API’s
fields
parameter.
Because it consults the index mappings, the fields
parameter provides several
advantages over referencing the _source
directly. Specifically, the fields
parameter:
- Returns each value in a standardized way that matches its mapping type
- Accepts multi-fields and field aliases
- Formats dates and spatial data types
- Retrieves runtime field values
- Returns fields calculated by a script at index time
The following search request uses the fields
parameter to retrieve values for
the event.type
field, all fields starting with process.
, and the
@timestamp
field. The request also uses the filter_path
query parameter to
exclude the _source
of each hit.
GET /my-data-stream/_eql/search?filter_path=-hits.events._source { "query": """ process where process.name == "regsvr32.exe" """, "fields": [ "event.type", "process.*", { "field": "@timestamp", "format": "epoch_millis" } ] }
Both full field names and wildcard patterns are accepted. |
|
Use the |
The response includes values as a flat list in the fields
section for each
hit.
{ ... "hits": { "total": ..., "events": [ { "_index": ".ds-my-data-stream-2099.12.07-000001", "_id": "OQmfCaduce8zoHT93o4H", "fields": { "process.name": [ "regsvr32.exe" ], "process.name.keyword": [ "regsvr32.exe" ], "@timestamp": [ "4100324829000" ], "process.command_line": [ "regsvr32.exe /s /u /i:https://...RegSvr32.sct scrobj.dll" ], "process.command_line.keyword": [ "regsvr32.exe /s /u /i:https://...RegSvr32.sct scrobj.dll" ], "process.executable.keyword": [ "C:\\Windows\\System32\\regsvr32.exe" ], "process.pid": [ 2012 ], "process.executable": [ "C:\\Windows\\System32\\regsvr32.exe" ] } }, .... ] } }
Use runtime fields
editUse the runtime_mappings
parameter to extract and create runtime
fields during a search. Use the fields
parameter to include runtime fields
in the response.
The following search creates a day_of_week
runtime field from the @timestamp
and returns it in the response.
GET /my-data-stream/_eql/search?filter_path=-hits.events._source { "runtime_mappings": { "day_of_week": { "type": "keyword", "script": "emit(doc['@timestamp'].value.dayOfWeekEnum.toString())" } }, "query": """ process where process.name == "regsvr32.exe" """, "fields": [ "@timestamp", "day_of_week" ] }
The API returns:
{ ... "hits": { "total": ..., "events": [ { "_index": ".ds-my-data-stream-2099.12.07-000001", "_id": "OQmfCaduce8zoHT93o4H", "fields": { "@timestamp": [ "2099-12-07T11:07:09.000Z" ], "day_of_week": [ "MONDAY" ] } }, .... ] } }
Specify a timestamp or event category field
editThe EQL search API uses the @timestamp
and event.category
fields from the
ECS by default. To specify different fields, use the
timestamp_field
and event_category_field
parameters:
GET /my-data-stream/_eql/search { "timestamp_field": "file.accessed", "event_category_field": "file.type", "query": """ file where (file.size > 1 and file.type == "file") """ }
The event category field must be mapped as a keyword
family field
type. The timestamp field should be mapped as a date
field type.
date_nanos
timestamp fields are not supported. You cannot use a
nested
field or the sub-fields of a nested
field as the timestamp
or event category field.
Specify a sort tiebreaker
editBy default, the EQL search API returns matching hits by timestamp. If two or more events share the same timestamp, Elasticsearch uses a tiebreaker field value to sort the events in ascending order. Elasticsearch orders events with no tiebreaker value after events with a value.
If you don’t specify a tiebreaker field or the events also share the same tiebreaker value, Elasticsearch considers the events concurrent and may not return them in a consistent sort order.
To specify a tiebreaker field, use the tiebreaker_field
parameter. If you use
the ECS, we recommend using event.sequence
as the tiebreaker field.
GET /my-data-stream/_eql/search { "tiebreaker_field": "event.sequence", "query": """ process where process.name == "cmd.exe" and stringContains(process.executable, "System32") """ }
Filter using Query DSL
editThe filter
parameter uses Query DSL to limit the documents on
which an EQL query runs.
GET /my-data-stream/_eql/search { "filter": { "range": { "@timestamp": { "gte": "now-1d/d", "lt": "now/d" } } }, "query": """ file where (file.type == "file" and file.name == "cmd.exe") """ }
Run an async EQL search
editBy default, EQL search requests are synchronous and wait for complete results before returning a response. However, complete results can take longer for searches across large data sets or frozen data.
To avoid long waits, run an async EQL search. Set wait_for_completion_timeout
to a duration you’d like to wait for synchronous results.
GET /my-data-stream/_eql/search { "wait_for_completion_timeout": "2s", "query": """ process where process.name == "cmd.exe" """ }
If the request doesn’t finish within the timeout period, the search becomes async and returns a response that includes:
- A search ID
-
An
is_partial
value oftrue
, indicating the search results are incomplete -
An
is_running
value oftrue
, indicating the search is ongoing
The async search continues to run in the background without blocking other requests.
{ "id": "FmNJRUZ1YWZCU3dHY1BIOUhaenVSRkEaaXFlZ3h4c1RTWFNocDdnY2FSaERnUTozNDE=", "is_partial": true, "is_running": true, "took": 2000, "timed_out": false, "hits": ... }
To check the progress of an async search, use the get
async EQL search API with the search ID. Specify how long you’d like for
complete results in the wait_for_completion_timeout
parameter.
GET /_eql/search/FmNJRUZ1YWZCU3dHY1BIOUhaenVSRkEaaXFlZ3h4c1RTWFNocDdnY2FSaERnUTozNDE=?wait_for_completion_timeout=2s
If the response’s is_running
value is false
, the async search has finished.
If the is_partial
value is false
, the returned search results are
complete.
{ "id": "FmNJRUZ1YWZCU3dHY1BIOUhaenVSRkEaaXFlZ3h4c1RTWFNocDdnY2FSaERnUTozNDE=", "is_partial": false, "is_running": false, "took": 2000, "timed_out": false, "hits": ... }
Another more lightweight way to check the progress of an async search is to use the get async EQL status API with the search ID.
GET /_eql/search/status/FmNJRUZ1YWZCU3dHY1BIOUhaenVSRkEaaXFlZ3h4c1RTWFNocDdnY2FSaERnUTozNDE=
{ "id": "FmNJRUZ1YWZCU3dHY1BIOUhaenVSRkEaaXFlZ3h4c1RTWFNocDdnY2FSaERnUTozNDE=", "is_running": false, "is_partial": false, "expiration_time_in_millis": 1611690295000, "completion_status": 200 }
Change the search retention period
editBy default, the EQL search API stores async searches for five days. After this
period, any searches and their results are deleted. Use the keep_alive
parameter to change this retention period:
GET /my-data-stream/_eql/search { "keep_alive": "2d", "wait_for_completion_timeout": "2s", "query": """ process where process.name == "cmd.exe" """ }
You can use the get async EQL search API's
keep_alive
parameter to later change the retention period. The new retention
period starts after the get request runs.
GET /_eql/search/FmNJRUZ1YWZCU3dHY1BIOUhaenVSRkEaaXFlZ3h4c1RTWFNocDdnY2FSaERnUTozNDE=?keep_alive=5d
Use the delete async EQL search API to
manually delete an async EQL search before the keep_alive
period ends. If the
search is still ongoing, Elasticsearch cancels the search request.
DELETE /_eql/search/FmNJRUZ1YWZCU3dHY1BIOUhaenVSRkEaaXFlZ3h4c1RTWFNocDdnY2FSaERnUTozNDE=
Store synchronous EQL searches
editBy default, the EQL search API only stores async searches. To save a synchronous
search, set keep_on_completion
to true
:
GET /my-data-stream/_eql/search { "keep_on_completion": true, "wait_for_completion_timeout": "2s", "query": """ process where process.name == "cmd.exe" """ }
The response includes a search ID. is_partial
and is_running
are false
,
indicating the EQL search was synchronous and returned complete results.
{ "id": "FjlmbndxNmJjU0RPdExBTGg0elNOOEEaQk9xSjJBQzBRMldZa1VVQ2pPa01YUToxMDY=", "is_partial": false, "is_running": false, "took": 52, "timed_out": false, "hits": ... }
Use the get async EQL search API to get the same results later:
GET /_eql/search/FjlmbndxNmJjU0RPdExBTGg0elNOOEEaQk9xSjJBQzBRMldZa1VVQ2pPa01YUToxMDY=
Saved synchronous searches are still subject to the keep_alive
parameter’s
retention period. When this period ends, the search and its results are deleted.
You can also check only the status of the saved synchronous search without results by using get async EQL status API.
You can also manually delete saved synchronous searches using the delete async EQL search API.
Run an EQL search across clusters
editThis functionality is in technical preview and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features.
The EQL search API supports cross-cluster search. However, the local and remote clusters must use the same Elasticsearch version.
The following cluster update settings request
adds two remote clusters: cluster_one
and cluster_two
.
PUT /_cluster/settings { "persistent": { "cluster": { "remote": { "cluster_one": { "seeds": [ "127.0.0.1:9300" ] }, "cluster_two": { "seeds": [ "127.0.0.1:9301" ] } } } } }
To target a data stream or index on a remote cluster, use the
<cluster>:<target>
syntax.
GET /cluster_one:my-data-stream,cluster_two:my-data-stream/_eql/search { "query": """ process where process.name == "regsvr32.exe" """ }
EQL circuit breaker settings
editWhen a sequence query is executed, the node handling the query
needs to keep some structures in memory, which are needed by the algorithm
implementing the sequence matching. When large amounts of data need to be processed,
and/or a large amount of matched sequences is requested by the user (by setting the
size query param), the memory occupied by those
structures could potentially exceed the available memory of the JVM. This would cause
an OutOfMemory
exception which would bring down the node.
To prevent this from happening, a special circuit breaker is used,
which limits the memory allocation during the execution of a sequence
query. When the breaker is triggered, an org.elasticsearch.common.breaker.CircuitBreakingException
is thrown and a descriptive error message is returned to the user.
This circuit breaker can be configured using the following settings:
-
breaker.eql_sequence.limit
-
(Dynamic) The limit for circuit breaker used to restrict
the memory utilisation during the execution of an EQL sequence query. This value is
defined as a percentage of the JVM heap. Defaults to
50%
. If the parent circuit breaker is set to a value less than50%
, this setting uses that value as its default instead. -
breaker.eql_sequence.overhead
-
(Dynamic) A constant that sequence query memory
estimates are multiplied by to determine a final estimate. Defaults to
1
. -
breaker.eql_sequence.type
-
(Static) Circuit breaker type. Valid values are:
-
memory
(Default) - The breaker limits memory usage for EQL sequence queries.
-
noop
- Disables the breaker.
-