[Sekoia] Retrieve the list of entity sources

[Lhorus6]

Use case

Sekoia provides a list of sources who have reported the information. Example: for an indicator, they list the sources that flagged this indicator.

The need is to know which source has reported the information, which is currently not retrieved in OpenCTI but provided by Sekoia. The information is contained in a custom Sekoia field, named "x_inthreat_sources_refs" (this field is a list of source name)

Current Workaround

Nothing, the data is lost

Proposed Solution

The various sources would have to be imported into the platform. Since STIX does not allow multiple “Author”, one idea would be to record them in labels, e.g. “source:Name1”, “source:Name2”, ...

One value in the "x_inthreat_sources_refs" list could be mapped as one label.

Additional Information

The "x_inthreat_sources_refs" list contains a list of STIX IDs (like the “CreatedBy” field), so we'll need to resolve the entities to retrieve their names

Would you be willing to submit a PR?

If needed, yes