Custom Output Question

[forensicmatt]

I am wanting to create a custom output. Something very similar to evtx::json_output::JsonOutput, but I want to be able to tweak how the json is generated just a little bit to get around some hurdles of ingesting the json into Elastic. Is it possible in 0.4.1 to create a custom output structure that implements BinXmlOutput? My issue is that some of the required modules are not public (for example evtx::model::xml::XmlElement).

Thanks in advance for the help.

[omerbenamram]

Hi @forensicmatt,

BinXmlOutput is somewhat of an implementation detail (as well as the inner model), which I'm not sure is sufficiently polished to be considered public API of the library.

Regarding your use case, I'm not sure I fully understand the issue, why not transform the current output JSON to fit your liking? Is there any information you think is missing in the current representation? I could improve the JSON output if necessary.

[forensicmatt]

Here is one example:

Mostly you have

<EventRecordID>3948</EventRecordID>

But there are also:

<EventID Qualifiers="16384">9009</EventID>

In JSON this is :

"EventID": 10001,

"EventID": {
  "#attributes": {
    "Qualifiers": 16384
  },
  "#text": 9009
},

Because the value of EventID can be either a Number, or an Object, this prevents ingesting records into elastic. My first thought was instead of naming an Elements attributes with #attributes, to make it "EventID_attributes": { } , this could then keep EventID: 9009 and have a separate object for ELEMENTNAME_attributes. Something of the nature should fix Values having multiple types. I am not sure how others would feel about the naming convention though so I was wanting to just implement it in a separate tool. I really don't want to do any type of XML to JSON conversion though because of the speed hurdle. Maybe you could provide a switch, or name how attributes are handled?

An example of what the json would look like:

"EventID": 9009,
"EventID_attributes": {
    "Qualifiers": 16384
},

[forensicmatt]

BinXmlOutput is somewhat of an implementation detail (as well as the inner model), which I'm not sure is sufficiently polished to be considered public API of the library.

Is this something that you would be open to making public and just stating that its not polished? If this was public I could just experiment with making my own Output right?

[forensicmatt]

I created a pull request for a solution that solves this issue without a performance hit: #53.