Phishing in Microsoft Teams

Phishing in Microsoft Teams

Microsoft Teams has become the heartbeat of modern business communication. But while it’s helping teams collaborate faster and more efficiently, it’s also opened a new door for cybercriminals. Phishing attacks—once confined to email—are now infiltrating Teams, often undetected until it’s too late.

If your business uses Teams, this is a threat you need to take seriously. Here’s what you need to know.

What is Microsoft Teams Phishing?

Phishing in Microsoft Teams is when cybercriminals send malicious links, attachments, or messages through the platform—posing as colleagues, clients, or even Microsoft itself. Unlike email, many businesses aren’t monitoring internal chat tools with the same scrutiny, which makes it fertile ground for attack.

What Does Phishing in Microsoft Teams Look Like?

  • A seemingly legitimate message from a colleague asking you to review a document
  • A shared link that redirects to a fake Microsoft login page
  • A message claiming “You’ve been removed from a Team—click here to resolve”
  • Invitations to join fake Teams meetings
  • Messages from compromised guest accounts within your Teams environment

Attackers may use compromised Microsoft 365 credentials to move laterally within your organisation, escalating access and stealing sensitive data.

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How Are Cybercriminals Getting In?

  1. Credential Theft – Stolen login details from other breaches or phishing emails.
  2. Compromised Guest Access – External users invited into your Teams environment may already be compromised.
  3. Token Hijacking – Stealing session tokens to bypass multi-factor authentication.
  4. Malware – Sent via file attachments or links in chat messages.
  5. Lack of Security Monitoring – Many businesses lack visibility into Teams activity.

What Can Companies Do to Prevent It?

✅ Enable Multi-Factor Authentication (MFA) It’s the first and most critical step. Without it, passwords alone are not enough.

✅ Restrict Guest Access Only allow verified, trusted partners into your Teams environment.

✅ Use Conditional Access Policies Control who can access Teams based on location, device, or risk level.

✅ Implement Advanced Threat Protection (ATP) ATP for Microsoft Teams can scan links and files for malware and phishing attempts.

✅ Educate Your Staff Phishing training should include real-world Teams scenarios—not just email examples.

✅ Audit and Monitor Teams Usage Use Microsoft’s built-in tools or third-party solutions to flag unusual activity.

✅ Keep Teams and Microsoft 365 Fully Updated Always apply patches and stay current with Microsoft’s latest security features.

What Should You Do if It Happens to You?

  1. Isolate the Threat Immediately revoke access or log out any compromised user accounts.
  2. Reset Passwords and Reissue MFA Tokens Ensure the attacker can’t return using stolen credentials.
  3. Conduct a Full Security Audit Determine how the attack occurred and whether any data was accessed.
  4. Inform Affected Parties Depending on the breach, you may need to inform staff, customers or the ICO.
  5. Seek Expert Support Immediately Responding quickly is critical—this is where expert IT support becomes invaluable.

The True Cost of a Breach

The average cost of a cyber breach for an SME in the UK is £65,000–£115,000 (source: NCSC), with many businesses facing long-term reputational damage, lost clients, and regulatory penalties.

Phishing attacks through Teams are not hypothetical.

They are happening now. And they’re targeting businesses that don’t think they’re on the radar.

Don’t Wait Until It’s Too Late

With a cyber-first approach, our Premium Service includes advanced protection, monitoring, training, and instant support if an incident ever occurs.

Book a call today at www.better-it.uk to safeguard your business from modern threats hiding in plain sight. We can walk you through Microsoft Teams or offer training courses to teach your team how to spot phishing attempts.