Your digital calendar is the command center of your workday. It tells you where to be, who you’re meeting with, and which deadlines are creeping up. You probably never second-guess it.
But what if your calendar suddenly started feeding you phishing links or malware notifications without you ever clicking accept? Unfortunately, malicious calendar alerts are sneaking into people’s schedules without their knowledge.
Researchers are warning that cybercriminals have found a clever way to abuse a feature in popular calendar apps, one that your team may not notice until it’s too late. It sounds wild, but harmless-looking reminders could lead straight to phishing attacks, malware notifications, or an account compromise.
The Innocent Calendar Feature That Turns Into a Backdoor for Criminals
Most major calendar platforms allow users to “subscribe” to external calendars. It’s handy when you want to follow industry events, company holidays, promotional updates, or even a team content calendar. Once you subscribe, those events show up automatically in your Google Calendar, Outlook, or Apple Calendar.
You wouldn’t think a dead domain could cause chaos, but it can. When a company doesn’t renew its domain, cybercriminals swoop in, buy the expired domain, and take over the existing calendar feed subscriptions.
Suddenly, instead of “20% off winter coats,” you get a calendar event titled “Your PayPal Account Requires Immediate Verification” with a very convincing-looking link.
Because the event comes from a “trusted” subscription, your calendar doesn’t flag it as spam. Suspicious events appear like any other appointment, often with notifications turned on by default. Those events can contain anything from fake security alerts to urgent bill payments, all with links that lead to phishing pages or malware-loaded websites.
Why These Calendar Scams Work So Well and the Signs To Look For
Cybercriminals know that most people trust what appears on their calendar. And that trust is exactly what scammers are banking on.
In fact, you’d be surprised how easy it is to miss malicious calendar alerts. They often share some obvious signs, though, including:
- Entries from unrecognized sources (always the first sign of a problem)
- Urgent language
- Reminders with external links that don’t match the displayed text
- Poor grammar or branding that looks slightly off
- Events scheduled outside of regular business hours
- Requests for personal or financial information
If an event feels “off,” it probably is. Encourage your staff to flag anything that appears unusual.
How To Protect Yourself and Your Team
Tightening your habits can help protect you from cybersecurity threats hidden in your calendar. You should:
- Review your calendar subscriptions and remove anything outdated.
- Turn off automatic event additions. Most platforms allow admins to block auto-added invitations.
- Use a dedicated calendar for external subscriptions. Separate your third-party calendars from your work schedule.
- Train your team on malicious calendar alerts during your phishing-awareness training.
- Enable link scanning for calendar invitations.
Keeping your calendars clean may not feel like a top-tier cybersecurity task, but malicious calendar alerts are a perfect way for hackers to fly under the radar. Trouble lands straight in your daily schedule and catches you when you’re distracted. A little awareness today prevents a very avoidable breach tomorrow.
