﻿---
title: CEF processor
description: Extracts fields from Common Event Format (CEF) message document. Here is a cef processor config When the above processor executes against the following...
url: https://www.elastic.co/elastic/docs-builder/docs/2585/reference/enrich-processor/cef-processor
products:
  - Elasticsearch
applies_to:
  - Elastic Cloud Serverless: Generally available
  - Elastic Stack: Planned
---

# CEF processor
Extracts fields from Common Event Format (CEF) message document.


| Name                  | Required | Default | Description                                                                                                                                                                                                                    |
|-----------------------|----------|---------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `field`               | yes      | -       | The field to be parsed.                                                                                                                                                                                                        |
| `target_field`        | no       | `field` | The field that the parsed structured object will be written into. Any existing content in this field will be overwritten.                                                                                                      |
| `ignore_missing`      | no       | `false` | If `true` and `field` does not exist or is `null`, the processor quietly exits without modifying the document                                                                                                                  |
| `ignore_empty_values` | no       | `true`  | If `true` then keys with empty values are quietly ignored in the document                                                                                                                                                      |
| `timezone`            | no       | UTC     | The default timezone used by the processor. Supports [template snippets](https://docs-v3-preview.elastic.dev/elastic/docs-builder/docs/2585/manage-data/ingest/transform-enrich/ingest-pipelines#template-snippets).           |
| `description`         | no       | -       | Description of the processor. Useful for describing the purpose of the processor or its configuration.                                                                                                                         |
| `if`                  | no       | -       | Conditionally execute the processor. See [Conditionally run a processor](https://docs-v3-preview.elastic.dev/elastic/docs-builder/docs/2585/manage-data/ingest/transform-enrich/ingest-pipelines#conditionally-run-processor). |
| `ignore_failure`      | no       | `false` | Ignore failures for the processor. See [Handling pipeline failures](https://docs-v3-preview.elastic.dev/elastic/docs-builder/docs/2585/manage-data/ingest/transform-enrich/ingest-pipelines#handling-pipeline-failures).       |
| `on_failure`          | no       | -       | Handle failures for the processor. See [Handling pipeline failures](https://docs-v3-preview.elastic.dev/elastic/docs-builder/docs/2585/manage-data/ingest/transform-enrich/ingest-pipelines#handling-pipeline-failures).       |
| `tag`                 | no       | -       | Identifier for the processor. Useful for debugging and metrics.                                                                                                                                                                |


## Examples


### Simple example

```js
{
  "cef": {
    "field": "message",
    "target_fields": "my_cef",
  }
}
```


### Full Example

Here is a cef processor config
```js
{
  "description" : "...",
  "processors" : [
    {
      "cef" : {
        "field" : "message",
        "target_field" : "my_cef",
      }
    }
  ]
}
```

When the above processor executes against the following message
```
CEF:0|Elastic|Vaporware|1.0.0-alpha|18|Web request|low|eventId=3457 requestMethod=POST slat=38.915 slong=-77.511 proto=TCP sourceServiceName=httpd requestContext=https://www.google.com src=1.2.3.4 spt=33876 dst=192.168.10.1 dpt=443 request=https://www.example.com/cart
```

it produces this result
```json
{
  "my_cef": {
    "severity": "low",
    "name": "Web request",
    "device": {
      "product": "Vaporware",
      "event_class_id": 18,
      "vendor": "Elastic",
      "version": "1.0.0-alpha"
    },
    "version": 0
  },
  "observer": {
    "product": "Vaporware",
    "vendor": "Elastic",
    "version": "1.0.0-alpha"
  },
  "destination": {
    "port": 443,
    "ip": "192.168.10.1"
  },
  "http": {
    "request": {
      "referrer": "https://example.com",
      "method": "POST"
    }
  },
  "source": {
    "geo": {
      "location": {
        "lon": -77.511,
        "lat": 38.915
      }
    },
    "port": 33876,
    "service": {
      "name": "httpd"
    },
    "ip": "1.2.3.4"
  },
  "event": {
    "code": 18,
    "id": 3457
  },
  "url": {
    "original": "https://example.com"
  },
  "network": {
    "transport": "TCP"
  }
}
```


### Example using `ignore_empty_values`

```js
{
  "cef": {
    "field": "message",
    "target_fields": "my_cef",
    "ignore_empty_values": false
  }
}
```

The final document will have fields with empty values when the corresponding CEF key has no value.
```json
{
  "my_cef": {
    "severity": "low",
    "name": "Web request",
    "device": {
      "product": "Vaporware",
      "event_class_id": 18,
      "vendor": "Elastic",
      "version": "1.0.0-alpha"
    },
    "version": 0
  },
  "http": {
    "request": {
      "referrer": "",
      "method": "POST"
    }
  }
}
```


### Exception scenarios

If the CEF message is invalid according to the spec then an exception is thrown by the processor.
Various scenarios include:
- CEF header does not start with `"CEF:"`
- Escaped pipe in extensions `(moo=this\|has an escaped pipe)`
- Equals symbol in message `(moo=this =has = equals\= )`
- Malformed escape sequences `(moo='Foo-Bar/2018.1.7; =Email:user@example.com;)`
- When CEF header is truncated `(CEF:0|Elastic|Mgmt|activityID=1111111111111111111)`
- If there are invalid timestamps, mac addresses, or ip addresses