Looking at a certificate for a web-site (in Windows/Google Chrome) I see it lists the following fields
- Serial number
- Signature algorithm
- Valid from
- Valid to
- Public Key
- Basic Constraints
- Certificate Policies
- CRL Distribution Points
- Enhanced Key Usage
- Key Usage
- Subject Alternative name
- Authority Information Access
- Thumbprint algorithm
Under some circumstances, the browser conveys what the problem may be.
Certificate not yet valid/expired: In this scenario either 'Valid From', or 'Valid To' is bad
Certificate for a different web-site: In this scenario 'Subject' is bad
I remember being told that on a suspicious certificate some fields should be verified manually/explicitly. I can't remember which fields amongst the above are relevant, nor what to look for in these fields.
For instance, what would happen if the field "Basic Constraints" in the certificate is bad? Or if the field "Certificate Policies" is bad?
Which fields in a suspicious certificate should I look at?
EDITED: Useful responses all around. Thank you!
What is the significance of the fields 'Basic Constraints', and 'Certificate policies'? I took a look at the RFC5280 but am too dense to figure out the significance to the description