MISP / MISP/misp-objects

SANs in x509 objects do not accept wildcards

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Python
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Description

Hi everyone,
I tried to add wildcards to an x509 object and it did not work. Many of the certificates we are using have wildcards as part of the SANs field.
According to RFC5280 wildcards are accepted in the SANs field:

Finally, the semantics of subject alternative names that include wildcard characters (e.g., as a placeholder for a set of names) are not addressed by this specification. Applications with specific requirements MAY use such names, but they must define the semantics.

Adding the wildcard to an x509 object did not work using the WebUI or the PyMisp library - presumably because the wildcard domain is being checked for being a valid hostname as the template uses the hostname type for dns_names.

One more thing: IP addresses are also allowed in the SANs field, but probably wouldn't pass the host validation (not tested).

Thanks for any help in advance!

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Research direction

Review the x509 object template and the hostname validation paths used by the WebUI and PyMISP, starting with how dns_names SAN values are checked. Reproduce the wildcard case and, if covered, an IP SAN, then verify that valid SAN values are accepted in both interfaces.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
security
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
48/100

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