GoKawiilSublime Security flags sharp rise in calendar-invite phishing attacks
Security firm Sublime has reported a surge in phishing attacks delivered via calendar invitations (ICS files) rather than traditional email, warning that such invites can bypass spam filters even when the accompanying email is blocked. The scams typically mimic legitimate meeting invites or payment notices, directing victims to fake login pages or malware disguised as Microsoft, Google, or PayPal services. Sublime says ICS phishing incidents rose roughly 33,000% between May and September, with attacks doubling or tripling month over month.
GoKawiil's interpretation of the reporting above, not reported fact.
The report suggests attackers are exploiting a blind spot in security tooling, since calendar services like Google Calendar and Microsoft 365 often auto-add invites separately from email filtering, making this vector harder to catch with existing defenses. This could push security vendors and IT teams to extend phishing protections beyond inboxes to scheduling software, while users may need new habits for scrutinizing unexpected calendar events.
- Calendar invitations (ICS files) are emerging as a phishing vector that can evade email spam filters.
- Sublime Security reported roughly a 33,000% increase in ICS phishing incidents between May and September.
- Scam invites often impersonate trusted services like Microsoft, Google, and PayPal to steal credentials or deliver malware.
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Published there as: “PSA: The calendar invite is the new phishing vector, and email filters aren't catching it”
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