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Content was updated: Sep 26, 2023
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## `parseCEF()`

Parse Common Event Format (CEF) encoded messages. Only CEF version 0 is supported. This function will skip any prefix up to the marker `CEF:0`.

Parameter | Type | Required | Default Value | Description
--- | --- | --- | --- | ---
`field`[a] | string | optional[b] | `@rawstring` | Field that holds the input in CEF form. This parameter specifies which field should be parsed. The default value parses the rawstring.
`headerprefix` | string | optional[b] | `cef.` | Prefix to the field names for the header fields.
`keeplabels` | boolean | optional[b] | `false` | Removes fields ending with label along with any field that has the same name, for example, cef.ext.csLabel and cef.ext.cs.
`labelprefix` | string | optional[b] | `cef.label.` | Prefix to the field names for the label fields.
`prefix` | string | optional[b] | `cef.ext.` | Prefix to extension fields. Fields in the CEF extension part are prefixed with this.
[a] The parameter name `field` can be omitted. [b] Optional parameters use their default value unless explicitly set.

Hide omitted argument names for this function

Show omitted argument names for this function

> Omitted Argument Names

> The argument name for `field` can be omitted; the following forms of this function are equivalent:

> logscale Syntax

>     parseCEF("value")

> and:

> logscale Syntax

>     parseCEF(field="value")

> These examples show basic structure only.

You may want to review the specification for CEF: ArcSight CEF Spec. For compatibility with legacy systems, this implementation allows the tab character (ascii `0x09`) in addition to space (ascii `0x20`) as separator for key value pairs in the extensions section. Literal backslash followed by t (as in `\t`) is not a separator, but re-interpreted line `\n` and `\r` in the specification.

### `parseCEF()` Syntax Examples

- From a log line like this:

  syslog

      Sep 19 08:26:10 host CEF:0 | security| threatmanager| 1.0| 100| detected a \\ in packet| 10| src=10.0.0.1 act=blocked a \\ dst=1.1.1.1

  CEF parse the @rawstring field to show how the CEF format is parsed with the default field names:

  logscale

      parseCEF(field=@rawstring)

  The following fields will be added to the event:

  Field | Value
  cef.version | `0`
  cef.device.vendor | `security`
  cef.device.product | `threatmanager`
  cef.device.version | `1.0`
  cef.event_class_id | `100`
  cef.name | `"detected a \\ in packet"`
  cef.severity | `10`
  cef.ext.src | `10.0.0.1`
  cef.ext.act | `"blocked a \\"`
  cef.ext.dst | `1.1.1.1`

- From a log line like this:

      CEF:0|Incapsula|SIEMintegration|1|1|Illegal Resource Access|3| fileid=3412341160002518171 sourceServiceName=site123.abcd.info siteid=1509732 suid=50005477 requestClientApplication=Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0 deviceFacility=mia cs2=true cs2Label=Javascript Support start=14532901213

  - Show the output of `parseCEF()` with changed header prefix:

    logscale

        parseCEF(headerprefix="new.header.")

    This will add the following fields to the event:

    Field | Value
    new.header.device.version | `1`
    new.header.device.vendor | `Incapsula`
    new.header.event_class_id | `1`
    new.header.device.product | `SIEMintegration`
    new.header.name | `Illegal Resource Access`
    new.header.version | `0`
    new.header.severity | `3`
    cef.label.Javascript Support | `"true"`
    cef.ext.requestClientApplication | `"Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0"`
    cef.ext.siteid | `1509732`
    cef.ext.sourceServiceName | `"site123.abcd.info"`
    cef.ext.fileid | `3412341160002518171`
    cef.ext.suid | `50005477`
    cef.ext.start | `14532901213`
    cef.ext.deviceFacility | `mia`

  - Show the output of `parseCEF()` with changed label prefix:

    logscale

        parseCEF(labelprefix="new.label.")

    This will add the following fields to the event:

    Field | Value
    cef.device.version | `1`
    cef.device.vendor | `Incapsula`
    cef.event_class_id | `1`
    cef.device.product | `SIEMintegration`
    cef.name | `Illegal Resource Access`
    cef.version | `0`
    cef.severity | `3`
    new.label.Javascript Support | `"true"`
    cef.ext.requestClientApplication | `"Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0"`
    cef.ext.siteid | `1509732`
    cef.ext.sourceServiceName | `"site123.abcd.info"`
    cef.ext.fileid | `3412341160002518171`
    cef.ext.suid | `50005477`
    cef.ext.start | `14532901213`
    cef.ext.deviceFacility | `mia`

  - Show the output of `parseCEF()` with changed extension prefix:

    logscale

        parseCEF(prefix="content.")

    This will add the following fields to the event:

    Field | Value
    cef.device.version | `1`
    cef.device.vendor | `Incapsula`
    cef.event_class_id | `1`
    cef.device.product | `SIEMintegration`
    cef.name | `Illegal Resource Access`
    cef.version | `0`
    cef.severity | `3`
    cef.label.Javascript Support | `"true"`
    content.requestClientApplication | `"Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0"`
    content.siteid | `1509732`
    content.sourceServiceName | `"site123.abcd.info"`
    content.fileid | `3412341160002518171`
    content.suid | `50005477`
    content.start | `14532901213`
    content.deviceFacility | `mia`

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