New Phishing Emails Now Evade Spam Filters
How Attackers Turn Familiar Calendar Invites Into Security Threats
Written by Bill Seybolt, Senior Cloud Advisor, Cumulus Global
A new kind of cyber attack is reaching employee inboxes by hiding inside meeting invitations and notifications. Attackers turn routine calendar invites into phishing delivery tools that currently bypass email defenses. We’re seeing these invites arrive with phishing links disguised as new voicemails, document reviews, and informational videos.
Key Takeaways
- ✓ Attackers route phishing links through real calendar invites to bypass email filters
- ✓ Fake verification prompts build user trust before asking for account logins
- ✓ Hidden guest lists and unfamiliar web addresses expose fraudulent invites
- ✓ Regular security training and modern inbox defenses prevent account takeovers

These notifications succeed because they’re authentic calendar invitations originating from valid Google Workspace or Gmail accounts.
Since the invite routes through Google Calendar’s infrastructure, email security tools view the traffic as authorized calendar activity. The interactive elements function normally, meaning that accepting an invite adds an event to your calendar, and clicking a meeting link opens Google Meet.
For example, this email poses as a Google Meet notification containing a new voicemail:

The invitation claims that a voice message is waiting for playback. The layout features functional Google Meet links alongside authentic calendar RSVP buttons. A telling warning sign appears under the attendee details, where the invite notes that the guest list is “too large to display.” However, this indicator is easy to overlook, and it is not uncommon for people in larger companies to receive invitations with legitimate large guest lists.
Think Twice Before You Click
Clicking the link redirects you to a convincing Cloudflare prompt asking to verify that you’re human.
That familiar checkpoint lowers your guard, because team members associate security tests with legitimate cloud services.
After passing the verification challenge, the browser lands on a forged authentication portal that looks like this:

The page mirrors a standard Google login screen, prompting the user to submit account credentials to access the recording.
If employees don’t inspect the browser address bar, the deception succeeds.
The address displays an external domain rather than Google’s legitimate sign-in service, so submitting a username and password hands over full control of your Google Workspace account.
3 Steps to Guard Your Business
Although this method of cyber attack is tough to block, here are three steps you can take to lower your risk:
- Teach your team how to recognize these attacks. Share this post and show them what a legitimate web address and sign-in page look like.
- Subscribe to a Security Awareness Training service to keep your team updated on common and emerging cybersecurity risks.
- Upgrade your email threat protection to a platform that lets staff report suspicious invites directly from their inbox. The underlying system learns from reported attempts, helping it block similar campaigns before they spread.
How We Help Keep Your Workspace Secure
Protecting your organization against evasive threats requires a coordinated defense, especially when someone clicks a deceptive link by mistake.
- Our Security and Compliance Assessments review your existing email protections alongside your broader security posture to identify configuration gaps.
- Through our Security CPR® model, we provide Security Awareness Training and Advanced Email Threat Protection as standalone solutions or bundled within our Managed Cloud Services packages.
If you’d like to evaluate your current defense or discuss how to protect your Google Workspace environment, book a brief, no-obligation, intro meeting with one of our Cloud Advisors. We’ll review your setup and help you decide on practical next steps for your team.
Bill Seybolt
Senior Cloud Advisor, Cumulus Global
Bill helps small and midsize organizations adopt practical cloud solutions that fit their priorities and budgets. He works directly with leaders and teams to evaluate workflows, identify goals, and map out clear rollout plans. Having helped over 200 organizations successfully adopt cloud solutions, he turns complex IT decisions into clear, measurable business gains.

Google Workspace is a comprehensive and secure platform that empowers organizations to be more productive, collaborative, and creative. This series explores the power of AI built within Google Workspace across each of the workspace apps. In this post, we cover AI in Gmail.
Allen Falcon is the co-founder and CEO of Cumulus Global. Allen co-founded Cumulus Global in 2006 to offer small businesses enterprise-grade email security and compliance using emerging cloud solutions. He has led the company’s growth into a managed cloud service provider with over 1,000 customers throughout North America.


Not just an email service, Google Apps is a business platform that enables efficiency and productivity by giving your team better communication and collaboration tools.

