West Lafayette, Indiana - An influx of spam invitations to Apple iPhone users is an indicator for future spam onslaughts, a Purdue University professor said.

The iOS calendar and iCloud photo sharing function received a barrage of spam invitations in recent weeks. The invitations, in some cases, tout everything from brand-name sunglasses to women's boots.

Marcus Rogers, professor and head of the Purdue Polytechnic Department of Computer and Information Technology, said this is a new trend for spam.

"This is just the beginning of the newer types of spam attacks that we will be seeing in the coming year," he said. "As vendors work to plug holes that spammers use to propagate their spam, these individuals then move to the next vulnerable protocols."

Prior to the fake calendar and photo sharing invitations, spam is usually characterized as simply clogging email inboxes.

But Rogers said this opens new doors to jeopardize users' online security.

"Since spam is a significant attack vector for data breaches and identity theft, this new trend is very troublesome," he said.

While email message filters have been the best line of defense against spam, Rogers said weapons to prevent this latest variety of spam aren't readily available to the average online user.

"Unfortunately there is not much a user can do proactively for the newer types of spam other than use common sense and be suspicious of odd looking invitations," he said.