OASIS Cyber Threat Intelligence (CTI) TC

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ID Contributing Properties

  • 1.  ID Contributing Properties

    Posted 06-20-2019 13:19
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    (Apologies if you already saw this on the cti users list)
     
    I m attempting to derive real deterministic ids for the examples in the spec.  Right now the SCO are expressed as stand-ins that look like type--00000000-0000-0000-0000-000000000000 .
     
    I m writing a script that will generate the ids but I have encountered some text in the spec which seems ambiguous.  They concern SCOs where a hash is one of the id contributing properties:
    Here are the three uses:
     
    For Artifact:
     
    hashes ,  payload_bin
    Where

    1.       if  hashes  exists
    only include 1 hash from this common ordered list (based on the following order of preference) [ md5, sha1, sha256, sha512 ]
    2.         if
    no hashes are defined and  payload_bin  exists include only the  payload_bin
     
    For File:
     
    hashes ,  name ,  extensions
    Where

    1.       if  hashes  exists
    include 1 hash from this ordered list [ md5, sha1, sha256, sha512 ] only

    2.       If no hashes

    a.       Include defined  extensions
    b.       Include
    defined  name
     
    For X509 Certificates:
     
    hashes ,  serial_number
    Where

    1.       if  hashes  exists
    include 1 hash from this ordered list [ md5, sha1, sha256, sha512 ] only

    2.       Include serial_number
     
    The way I read this, Artifact and File only include other properties if there are no hashes available, but X509 Certificates always includes serial_number.
     
    If that is the case, then I would probably want to clean up the text but I m not sure that this is what was intended.
     
    Can someone more explicitly describe the use of the contributing properties for these three types?
     
                    Rich
    -- 
    Rich Piazza
    The MITRE Corporation
    781-271-3760