Thanks to one particularly aggressive campaign from a junk mailer, [iMessage spam] accounts for more than 30 percent of all mobile spam messages [...]
“It’s almost like a spammer’s dream,” says Cloudmark’s Tom Landesman. “With four lines of code, using Applescripts, you can tell your Mac to send message to whoever they want.”
Part of the issue is that spammers don’t need your cell number to send you an iMessage: your email address is all they need if you’ve linked that address to iMessage.
Apple has already taken some steps to address the issue, limiting the rate at which iMessages can be sent – but spammers can work around that with multiple iMessage accounts, which require only an email address to create. Apple also allows spam-reporting, but as this requires an extremely clunky manual approach, few bother.
You have to email the company a screenshot of the spam, the phone number or email address of the spammer, and the date and time it was sent.
Wired says that the reporting procedure also seems ineffective: one address it reported was still active five days later.
One solution for users is to only allow iMessages from those in your contacts, by going into Settings >Notification Center > Messages and then scrolling right down to the bottom of the screen to change the default Show alerts from everyone to Show Alerts from My Contacts.
iMessages were the subject of controversy (and a lawsuit) when text messages continued to be sent to an inactive iMessage account for some users who switched away from an iPhone. Apple responded by promising a bug fix.