As far as I know this is related to the change of API format that was introduced in Nessus 8. I do not believe this addon currently works for the new API structure, but it certainly should be able to. I have seen some projects on github that are able to pull from Nessus 8.x so my plan was to try to edit this Splunk app with similar logic.
Some additional API information from the Tenable community boards:
Scan exports are still fully supported in 8.1.0. This functionality may have changed in how it needs to be queried, so it is very important to read the API documentation for your existing version for 3rd party integrations.
The XML format you're referring to we call the 'nessus' format, but it does follow the xml format as well, that is just how it is labelled in our system.
In order to properly gather a scan result as a XML, you will first need to trigger the export by sending an authenticated (using the api keys) post request to:
Https://x.x.x.x:8834/scans/{scan_id}/export
The body of this request should contain json formatted data such as this:
{ "format": "nessus" }
In response you will get JSON formatted data such as:
{ "token": , "file": }
taking that file_id, you would then be able to gather the export with the following GET request:
https://x.x.x.x/scans/{scan_id}/export/{file_id}/download
