Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

[RFC] Proposal to define ECS-compliance - Stage 1 #1868

Merged
merged 10 commits into from
Apr 13, 2022
Merged

[RFC] Proposal to define ECS-compliance - Stage 1 #1868

Changes from all commits
Commits
Show all changes
10 commits
Select commit Hold shift + click to select a range
343cbf3
initial draft for stage 1
ebeahan Mar 31, 2022
38c1368
update placeholder for PR
ebeahan Mar 31, 2022
fa68b3b
use clearer language on array expectation
ebeahan Apr 12, 2022
e103028
Merge branch 'main' into rfc/ecs-compliance/stage-1
ebeahan Apr 12, 2022
843db26
an editing round
ebeahan Apr 13, 2022
bc3ba28
more edits
ebeahan Apr 13, 2022
19e00f7
fix spacing in examples
ebeahan Apr 13, 2022
24cac37
spaces not tabs
ebeahan Apr 13, 2022
3eb567d
set rfc number and date
ebeahan Apr 13, 2022
88c09e2
Merge branch 'main' into rfc/ecs-compliance/stage-1
ebeahan Apr 13, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
282 changes: 282 additions & 0 deletions rfcs/text/0032-definition-of-ecs-compliance.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,282 @@
# 0032: Definitions of ECS Compliance
<!-- Leave this ID at 0000. The ECS team will assign a unique, contiguous RFC number upon merging the initial stage of this RFC. -->

- Stage: **1 (draft)** <!-- Update to reflect target stage. See https://elastic.github.io/ecs/stages.html -->
- Date: **2022-04-13** <!-- The ECS team sets this date at merge time. This is the date of the latest stage advancement. -->

<!--
As you work on your RFC, use the "Stage N" comments to guide you in what you should focus on, for the stage you're targeting.
Feel free to remove these comments as you go along.
-->

Events described as "compliant" follow the [ECS guidelines and best practices](https://www.elastic.co/guide/en/ecs/current/ecs-guidelines.html). While the guidelines provide an overview, detailed guidance aids ECS producers and consumers. This proposal aims to standardize what is and is not expected of an ECS-compliant event.

This document's usage of the terms _must_, _must not_, _should_, _should not_, _required_, and _may_ are in accordance with [IETF RFC 2119](https://www.ietf.org/rfc/rfc2119.txt).

## Fields

The following sections describe the required, suggested, and optional practices. Later sections include more detailed examples of certain items.

### Minimum requirements

An ECS-compliant event MUST:

* populate the `@timestamp` field with the date/time the event originated.
* set `ecs.version` to the ECS version this event conforms.
* index all ECS fields using the data type defined in the schema. A different type from the same type family (e.g., `keyword` for `wildcard`) may substitute
* use nested fields over dotted. ECS events should use nested objects, `{ "log": { "level": "debug" }}`), over dotted field names, `{ "log.level": "debug" }`.

### Recommended guidelines

ECS-compliant events SHOULD:

* map the contents of the original event to as many ECS fields as possible.
* populate the top-level `message` field.
* store the entire raw, original event in `event.original`. Disable indexing and doc_values on `event.original` to reduce store.
* If a field expects an array, the value should always be an array even if the array contains one value (for example, `[ 10.42.42.42 ]`).
* lowercase the value if the field's description calls for it.
* set the event categorization fields using the [allowed values](https://www.elastic.co/guide/en/ecs/current/ecs-category-field-values-reference.html).
* populate `source.*` and `destination.*` as a pair, when possible.
* populate `source.*`/`destination.*` if `client.*`/`server.*` are populated.
* copy all relevant values into the `related.*` fields.
* use "breakdown" fields. Breakdown fields take an original value and deconstruct it. Examples include `user_agent.*` or `.domain`, `.sub_domain`, `.registered_domain`, etc.
* duplicate the `.address` field value into either `.ip` or `.domain`. Dot not populate the `.ip` and `.domain` fields directly.

### Optional

ECS-compliant events MAY:

* use custom fields alongside ECS fields in an event. Use proper names for custom fields over generic concept names. Proper names reduce the chance of a future conflict. Nest custom fields inside an object and not leaf fields at the base of the event.
* remove unused ECS fields or entire field sets from an index mapping.
* add multi-fields not defined by ECS. For example, a text multi-field with a custom analyzer.

<!--
Stage 2: Add or update all remaining field definitions. The list should now be exhaustive. The goal here is to validate the technical details of all remaining fields and to provide a basis for releasing these field definitions as beta in the schema. Use GitHub code blocks with yml syntax formatting, and add them to the corresponding RFC folder.
-->

## Usage

An ECS-compliant event will have `@timestamp`, `ecs.version`, and at least one other field. Dots in the ECS field name represent a nested object structure. The following mapping indexes as the correct data types into Elasticsearch:

```json
{
"@timestamp": "2022-03-31T18:48:35.000Z",
"ecs": {
"version": "8.1.0"
},
"message": "example.com 10.0.0.2, 10.0.0.1, 127.0.0.1 - - [07/Dec/2016:11:05:07 +0100] \"GET /ocelot HTTP/1.1\" 200 571 \"-\" \"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:49.0) Gecko/20100101 Firefox/49.0\""
}
```

```json
{
"mappings" : {
"properties" : {
"@timestamp" : {
"type" : "date"
},
"ecs" : {
"properties" : {
"version" : {
"type" : "keyword",
"ignore_above" : 1024
}
}
},
"message" : {
"type" : "match_only_text"
}
}
}
}
```

This compliant event builds on the required guidelines and incorporates many recommended practices.

```json
{
"agent": {
"name": "test",
"id": "a0e86cd2-d38b-4801-8d54-db5f2fb7f7e1",
"ephemeral_id": "8568c102-6c2d-495d-800b-bc5b89cde1b6",
"type": "filebeat",
"version": "8.1.2"
},
"log": {
"file": {
"path": "/var/log/nginx/access.log"
},
"offset": 2716
},
"source": {
"address": "192.168.64.1",
"ip": "192.168.64.1"
},
"destination": {
"address": "192.168.64.2",
"ip": "192.168.64.2"
},
"url": {
"path": "/",
"original": "/"
},
"tags": [
"nginx-access"
],
"@timestamp": "2022-03-31T18:48:35.000Z",
"ecs": {
"version": "8.0.0"
},
"related": {
"ip": [
"192.168.64.1",
"192.168.64.2",
"fe80::9c5f:77ff:fe74:604"
]
},
"host": {
"hostname": "test",
"os": {
"kernel": "5.4.0-105-generic",
"codename": "focal",
"name": "Ubuntu",
"type": "linux",
"family": "debian",
"version": "20.04.4 LTS (Focal Fossa)",
"platform": "ubuntu"
},
"ip": [
"192.168.64.2",
"fe80::9c5f:77ff:fe74:604"
],
"name": "test",
"id": "39c062dece654ac393c9f62fc2be2b11",
"mac": [
"9e:5f:77:74:06:04"
],
"architecture": "x86_64"
},
"http": {
"request": {
"method": "GET"
},
"response": {
"status_code": 304,
"body": {
"bytes": 0
}
},
"version": "1.1"
},
"event": {
"agent_id_status": "verified",
"ingested": "2022-03-31T18:48:38Z",
"timezone": "-05:00",
"created": "2022-03-31T18:48:37.472Z",
"kind": "event",
"category": [
"web"
],
"type": [
"access"
],
"dataset": "nginx.access",
"outcome": "success"
},
"user_agent": {
"original": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.84 Safari/537.36",
"os": {
"name": "Mac OS X",
"version": "10.15.7",
"full": "Mac OS X 10.15.7"
},
"name": "Chrome",
"device": {
"name": "Mac"
},
"version": "99.0.4844.84"
}
}
```

1. Maps as many fields as possible based on what was available in the event. An Elasticsearch ingest pipeline also populates more fields.
2. Fields expecting arrays, like `event.category`, use arrays even for a single value.
3. Adds the event categorization fields (`event.kind`, `event.category`, `event.type`, and `event.outcome`).
4. Populates `source.*` and `destination.*` fields as a pair.
5. Concatenate all IP addresses into the `related.ip` field.
6. Both `source.address` and `destination.address` copy the `*.address` to its sibling `.ip` field.
7. The original user-agent value populates `user_agent.original`. Other fields hold the broken down values: `user_agent.os.*`, `user_agent.name`, `user_agent.version`, etc.

<!--
Stage 1: Describe at a high-level how these field changes will be used in practice. Real world examples are encouraged. The goal here is to understand how people would leverage these fields to gain insights or solve problems. ~1-3 paragraphs.
-->

## Source data

<!--
Stage 2: Included a real world example source document. Ideally this example comes from the source(s) identified in stage 1. If not, it should replace them. The goal here is to validate the utility of these field changes in the context of a real world example. Format with the source name as a ### header and the example document in a GitHub code block with json formatting, or if on the larger side, add them to the corresponding RFC folder.
-->

<!--
Stage 3: Add more real world example source documents so we have at least 2 total, but ideally 3. Format as described in stage 2.
-->

The ECS-compliant guidance formalized applies to all ECS data sources.

## Scope of impact

This proposal is informational and includes no changes to ECS. Beats, Elastic Agent, and APM users already gain the benefits of ECS-compliant data. Custom sources will benefit normalizing their data into ECS-compliant events.

## Concerns

<!--
Stage 1: Identify potential concerns, implementation challenges, or complexity. Spend some time on this. Play devil's advocate. Try to identify the sort of non-obvious challenges that tend to surface later. The goal here is to surface risks early, allow everyone the time to work through them, and ultimately document resolution for posterity's sake.
-->

### Arrays in ECS

Any field can contain zero or more values of the same type. There is no dedicated [array type](https://www.elastic.co/guide/en/elasticsearch/reference/current/array.html) in Elasticsearch. Why distinguish array vs. non-array fields in ECS?

While Elasticsearch is permissive, other software languages and configurations support array constructs. Components adopting ECS are able to expect what fields do and don't use arrays.

<!--
Stage 2: Document new concerns or resolutions to previously listed concerns. It's not critical that all concerns have resolutions at this point, but it would be helpful if resolutions were taking shape for the most significant concerns.
-->

<!--
Stage 3: Document resolutions for all existing concerns. Any new concerns should be documented along with their resolution. The goal here is to eliminate risk of churn and instability by ensuring all concerns have been addressed.
-->

## People

The following are the people that consulted on the contents of this RFC.

* @ebeahan | author, sponsor

<!--
Who will be or has been consulted on the contents of this RFC? Identify authorship and sponsorship, and optionally identify the nature of involvement of others. Link to GitHub aliases where possible. This list will likely change or grow stage after stage.

e.g.:

* @Yasmina | author
* @Monique | sponsor
* @EunJung | subject matter expert
* @JaneDoe | grammar, spelling, prose
* @Mariana
-->


## References

<!-- Insert any links appropriate to this RFC in this section. -->

### RFC Pull Requests

<!-- An RFC should link to the PRs for each of it stage advancements. -->

* Stage 1: https://github.com/elastic/ecs/pull/1868

<!--
* Stage 1: https://github.com/elastic/ecs/pull/NNN
...
-->