Recently, cybersecurity researchers uncovered a phishing campaign where attackers abused Microsoft Teams invitations to trick users into revealing credentials. The attackers created invites that looked like legitimate billing or subscription notifications and sent them through real Microsoft systems. Because the messages carried familiar Teams branding, many recipients trusted them and followed the instructions, which often led to fake support numbers or phishing sites designed to capture login information.

This type of attack works because people tend to trust messages delivered through collaboration platforms. It reflects a growing trend where cybercriminals no longer rely solely on email spoofing. Instead, they are leveraging trusted tools like Microsoft Teams to deliver malicious content directly into business workflows.

In this week’s Tech Tip Tuesday, we’ll explain how these attacks work, what signs to watch for, and how you can protect yourself and your organization from this evolving threat.

How Teams Messages Are Being Used in Attacks

Attackers exploit Teams’ built-in messaging and invitation features to send content that appears official. In some cases, they create fake workspaces or use compromised accounts to distribute urgent messages that claim a billing issue, subscription expiration, or security problem.

Because these messages are delivered through Microsoft’s own infrastructure, they often bypass traditional email security filters. Once a user engages, the attacker may redirect them to a fake login page, prompt them to call a fraudulent support number, or continue the conversation through social engineering.

The end goal is usually to gain access to Microsoft 365 accounts, which can then be used to read emails, send messages internally, or access company files.

Why This Is Dangerous

Once a user engages with the malicious content, the attacker’s goal can vary but often includes:

• Harvesting Microsoft 365 credentials — leading to email and account takeover
• Redirecting to phishing pages designed to collect usernames and passwords
• Social engineering follow-ups such as fake support calls or urgent messaging
• Establishing persistent access to communication platforms and cloud files

Because the initial message may look genuine and use official Microsoft branding, many users are more likely to trust it at first glance — especially in a business setting where Teams activity is part of daily workflow.

How to Spot Suspicious Teams Messages

Here are signals that a Teams message may be a phishing attempt:

1. Unexpected invitations – Teams invites you did not request or are from unfamiliar sources.
2. Urgent billing language – Messages reference payments you do not recognize, fake invoice IDs, or immediate action requirements.
3. Inconsistent text or characters – Some scam messages use look-alike characters or odd spacing to bypass filters.
4. Requests for credentials or support contact – Legitimate Teams alerts will never ask you to call an external support number or enter your credentials in a non-Microsoft portal.
5. Links that don’t match their labels – Hover before clicking to see the actual URL and ensure it matches the displayed text.

Best Practices to Protect Yourself

• Always verify the sender and the context of any unexpected Teams message by contacting the person or department through another method.
• Never enter your login credentials through a link sent in Teams. Instead, open your browser and navigate directly to the official Microsoft sign-in page.
• Enable multifactor authentication on your Microsoft accounts. This adds an extra layer of protection even if a password is compromised.
• Report suspicious messages directly within Teams by selecting the message options and choosing Report.
• Keep Teams, your operating system, and your browser updated so security patches are applied.
• Finally, make sure employees and family members know that collaboration tools can be abused just like email. Awareness remains one of the strongest defenses.

The Bottom Line

Cybercriminals are adapting their tactics by using trusted platforms like Microsoft Teams to launch convincing phishing campaigns. Understanding how these attacks work and knowing what to watch for can prevent a single message from turning into a major security incident.

If you would like help reviewing your Microsoft 365 security settings, enabling multifactor authentication, or providing awareness training, please feel free to contact us at 818-501-2281 or email us at info@ceocomputers.com.