Correct me if I am wrong but I understood that certificate validation was processed by the information in the certificate to be validated (CDP or AIA extension). If the CDP location contains a valid CRL URL and that CA's CRL is not already in cache, then the CRL is retreived from that CDP URL in the certificate. If a person was able to inject a modified CRL into that CDP URL, or redirect the client machine to an alternate server for LDAP/HTTP CRL download, and CAPI is not validating signatures on CRL's then a person could use a revoked certificate for access to systems among other things. While this may not be a bug I think it would be a wise security practice to validate a signature if it is there. Neil > * Faro Poplar wrote: >> Has anyone noticed that Windows doesn't verify the digital signature >> of CRL files (*.crl). > > Yes, I noticed that about 2 years ago. IMO this is no security issue. > CRLs are retrieved from the certificate store via CertGetCRLFromStore. > Sane use of CertGetCRLFromStore makes sure only properly signed CRLs are > used (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ > seccrypto/security/certverifycrlrevocation.asp). > > Thomas Walpuski >
