Microsoft Teams has evolved from a simple collaboration tool into the central nervous system of modern workplaces. But this growth has brought with it increased attention from bad actors looking to exploit it. Last month, Microsoft revoked 200 fraudulent certificates and issued new guidance to help organizations stay safe amid a surge of Teams-related attacks.
Protecting Teams in this environment requires new security measures that safeguard sensitive data while maintaining the platform’s core emphasis on open collaboration.
To gain insight into these challenges, we spoke with Rob Hughes, Chief Information Security Officer at RSA, about the evolving threat landscape surrounding Microsoft Teams and what organizations need to do differently to protect themselves.
The Trust Problem: Teams’ Biggest Vulnerability
The fundamental security challenge with Teams isn’t necessarily the application itself but how users perceive and interact with it. Hughes identifies this trust dynamic as the platform’s most exploitable weakness.
“Teams poses significant risks, primarily due to attackers exploiting the inherent trust users place in the application and its integration with other Microsoft services,” Hughes explains. “People are more likely to trust a random message or phone call from Teams than they would on their phone. That makes Teams an attractive target.”
Hughes notes this is an issue that has been evolving ever since the likes of Zoom first took off. “Like most risks, there’s a game of cat and mouse with Teams. We saw similar patterns when Zoom took off during the pandemic: attackers started to get interested in what these applications could do, what their configurations were, how launchers prioritized easy setup over long-term security,” he says.
This constant adaptation shows how attackers learn to exploit systems more effectively over time. Combined with the high level of trust users place in Teams, social engineering becomes particularly effective.
Because Teams is integrated into OneDrive, SharePoint, Outlook, and third-party apps, a single exploited account can become a gateway to the broader Microsoft ecosystem, amplifying the impact of these attacks.
“One of the challenges with Teams is that it’s not separate from other Microsoft applications: there’s a great deal of shared risk when organizations have so many eggs in one Microsoft basket,” Hughes notes. “Third-party integrations make for even greater complexity and provide users with more opportunities to overshare.”
This interconnectedness means that the trust administrators place in Teams accounts can allow an attacker to move laterally across an organization’s ecosystem, turning a single compromised account into a much larger security incident.
Solutions: Building a Proactive, Resilient Defense
Modern realities mean traditional, reactive security measures are no longer sufficient to protect Teams. Hughes emphasizes a shift to Zero Trust principles, where trust is never assumed and verification happens continuously, as a solution.
Central to this approach is out-of-band identity validation, which involves verification methods that don’t rely on potentially compromised Microsoft applications. “If I suspect a user’s Microsoft account has been compromised, I shouldn’t use a Microsoft application to contact them,” Hughes explains.
Visibility into permissions and access across Teams and the wider Microsoft ecosystem is also critical. Hughes highlights Identity Security Posture Management (ISPM) as a framework that helps organizations map, monitor, and reduce access-related risks. “Organizations need a complete view of access and entitlements—including service and machine accounts—to secure Teams,” he notes.
Finally, separating security and infrastructure administration helps limit the impact of any single compromise. By diversifying responsibilities and access, organizations reduce the likelihood that a breach in one area automatically exposes others.
“Many of our customers value separation between the administration of an organization’s tech environment and its identity practice,” Hughes adds.
Together, these strategies create a proactive, resilient approach to Teams security that assumes compromise is possible but preventable.
Looking Ahead: Protecting Teams in an Integrated World
As Teams continues to evolve into the backbone of enterprise collaboration, organizations must recognize that security is no longer just about the application itself: it’s about the ecosystem it connects. The trust users place in Teams, while essential for collaboration, can become the vector attackers exploit to move laterally across Microsoft services and third-party apps.
Implementing a Zero Trust mindset, combined with ISPM and administrative separation is key. But it’s not a one-off exercise: organizations need continuous oversight, regular audits, and adaptive security measures to keep pace with new integrations and evolving threat tactics.
The goal is to maintain seamless collaboration while keeping sensitive data secure. By proactively addressing trust, visibility, and access risks, organizations can protect sensitive data while allowing users to trust the tools they interact with, ensuring Teams remains a powerful enabler of productivity rather than a potential liability.
