Calendar-invite phishing surged 33,000% in five months

Security researchers at Sublime warn that ICS phishing via calendar invitations grew roughly 33,000% between May and September. Attackers send the same lure to email and calendars at once, and spam filters often miss it because Google Calendar and Microsoft 365 handle invitations differently.

• ICS phishing attacks rose about 33,000% from May to September
• Monthly growth exceeded 1,000% in the months after June
• Invites bypass spam filters in Google Calendar and Microsoft 365
• Links lead to fake Microsoft, Google and PayPal pages