Apple has finally purged the imprimatur of disgraced web authentication authority DigiNotar from its Mac operating system.

In an update released Friday, Apple removed multiple DigiNotar root certificates from the Lion and Snow Leopard versions of Mac OS X. The move came nine days after the discovery that the Netherlands-based authority issued a counterfeit SSL certificate for Google.com that was used to spy on people in Iran. An investigation later revealed that DigiNotar had failed to warn browser makers that it issued at least 531 bogus credentials following a security breach that gave attackers free rein over its certificate issuance system for weeks.

Within hours of the discovery, Google and Mozilla issued updates that caused their browsers and email programs to reject most SSL certificates issued by DigiNotar. Users of Windows Vista and later versions of the Microsoft operating system were also protected, although it wasn't until earlier this week that Windows XP users received the same defense.

Apple's delayed response comes in sharp contrast. Not only has it taken longer to issue the update, but it didn't utter a peep of warning to its users in the intervening time. At time of writing, there were no updates available that purged the untrustworthy DigiNotar root certificates from iOS, meaning iPhone and iPad users are still vulnerable to fraudulent DigiNotar certificates.

Users of Google's Android OS for smartphones also remain wide open.

The threats Apple and Google have failed to protect their users against are by no means theoretical. At least one of the certificates has already been encountered by at least 300,000 people, mostly in Iran, as they accessed Gmail or other protected Google services. Trend Micro has more details about the certificate here. ®