GMX is warning users of a new type of spam using fake calendar appointments known as “calendar spam” looking to give attackers multiple opportunities to infect victims.

The threat comes from the threat actor sending the fake appointment invitation via email but unlike traditional spam which comes in the form of unwanted messages, calendar spam comes with unwanted calendar appointments attached.

The calendar attachment can attack when the invitation is sent, when its an entry on the calendar and if the appointment contains a reminder function, giving the sender multiple opportunities to spam the victim.

“Currently, calendar spam accounts for seven percent of all digital appointment invitations – and this figure is rising,”  Jan Oetjen, managing director of GMX, said in a Jan. 31 press release. “If, for example, you receive special ‘discounts,’ or the sender is unknown, then users should be extremely skeptical.”

One of the ways users can get rid of the calendar spam is to create a new calendar, move the calendar spam entry to the new calendar and then delete the created calendar including the fake date.