Spammers have discovered a new method to infiltrate your life. Over the past few months, Apple users have been reporting strange iCal invites from miscellaneous accounts that clearly aren't legitimate. These fake invites are hard to handle: Unlike email, calendar invites can't be marked as spam, and declining the invites will alert the spammers that the iCloud account is active — which could lead to even more invites. What are you supposed to do?
An iOS update would best remedy this situation, but there are a couple workarounds that can help you in the meantime. Here's what you can do if you receive spam calendar invites:
Reroute push notifications to iCloud email
By default iCal will send event invites to your iPhone as a push notification, but you can change this setting to reroute invites to your iCloud email. Not only will this prevent fake invites from bombarding your phone, but your email account should identify these events as spam and rightly filter them as such.
To change this setting, you'll have to visit the iCloud Calendar page on a computer (you can't access iCloud.com on mobile Safari). Click on the gear icon in the lower-left corner of the screen to access Settings. From that menu, select Preferences. Then hit the Advanced tab and change the Invitations option from "In-App Notifications" to "Email to iCloud Address."
There is a downside to this: Now all calendar events will be sent to your iCloud email, meaning you'll have to routinely check it if you want to see invites from family or friends.
Disable the iCloud calendar
The above option is suited for users who actively use iCal — this one is for those who don't (Google Calendar is better anyway, right?). If your iCloud calendar is expendable, just head to your iPhone's Settings and select iCloud to disable the app. All push notifications from the spammers will halt.