[UPDATE: MasterCard has fixed the issue]
(LiveHacking.Com) – It appears as if one part of the MasterCard Australia Website has not been audited recently as it is using an untrusted digital certificate. The error was noticed on the https://migs.mastercard.com.au/ site when a Mastecard customer was trying to pay for some insurance.
Since this is a financial site which processes financial transactions, the certificate on the site should be one globally recognized. Without a valid certificate any user of the service can not be sure that the site hasn’t been spoofed or hijacked in some way.
A copy of the exported certificate can be downloaded from here.