Microsoft Teams security flaws expose organisation to advanced social engineering threats

Critical vulnerabilities within Microsoft Teams have been uncovered, revealing significant risks that could allow cybercriminals to impersonate executives, manipulate messages, and forge identities, with potentially devastating consequences for business communications and security.

Cybercriminals came dangerously close to exploiting critical vulnerabilities within Microsoft Teams, exposing serious risks to business communications at the highest levels of organisations. Researchers from Check Point uncovered four major security flaws that could allow attackers not only to impersonate executives but also manipulate messages, alter notifications, and forge identities during video and audio calls, severely undermining trust within this widely used collaboration platform.

Microsoft Teams has become an integral tool for businesses of all sizes, deeply embedded in the Microsoft ecosystem and facilitating everyday communication. However, this ubiquity also makes it a prime target for attackers seeking to exploit trust-based features. The vulnerabilities identified include message manipulation without triggering the usual “Edited” label, notification spoofing by altering sender display names, the ability to rename private chat threads to impersonate trusted contacts, and forged caller identities in voice and video meetings. Such exploits open pathways for sophisticated social engineering, financial fraud, and even cyber espionage.

For instance, the message manipulation flaw allows attackers to subtly alter sent communications, potentially deceiving employees into following fraudulent instructions or clicking malicious links originated from seemingly reliable internal sources. Notification spoofing exploits the platform’s parameter handling to make alerts appear as though they come from senior executives, increasing the likelihood of urgent action based on illegitimate requests. Similarly, the renaming of chat conversations to impersonate key figures like HR representatives or company executives creates fertile ground for information theft or internal deception. The forged caller identity vulnerability enables attackers to falsify incoming call details, amplifying risks during sensitive or high-stakes meetings.

The implications extend far beyond theoretical concerns. Attackers could exploit these vulnerabilities to request emergency wire transfers, deliver malware-laden files, conduct misinformation campaigns, or disrupt confidential discussions. The potential for advanced persistent threat (APT) groups to leverage such flaws for espionage or sabotage adds a further layer of urgency. This cascade of risks underscores how trust, the foundation of collaboration, has emerged as a critical attack surface in modern enterprise environments.

In response, Microsoft reportedly addressed these vulnerabilities with patches released by October 2025. Nevertheless, security experts emphasise that platform-level fixes represent only an initial step towards safeguarding organisational communication. A comprehensive defence requires a multi-layered strategy incorporating zero-trust principles, continuous user and device verification, real-time threat inspection of collaboration content, data loss prevention measures, rigorous user training to challenge suspicious requests, enhanced monitoring via behavioural analytics, and strict access segregation and privilege minimisation.

These recommendations reflect the broader reality that cyber attackers increasingly manipulate human behaviors and familiar interfaces, targeting trust rather than simply technical weaknesses. Recent cybercrime campaigns highlight this trend: phishing attacks spoofing Microsoft Teams notifications have surged, deceiving users with convincingly forged login prompts aimed at credential theft across sectors such as energy, retail, and hospitality. Attackers have also leveraged Microsoft 365’s email features like ‘Direct Send’ to bypass security filters and impersonate internal users. More alarmingly, voice phishing (vishing) attacks exploiting Microsoft Teams have been used to push remote access trojans like DarkGate, demonstrating the expanding toolset of cyber adversaries.

Further vulnerabilities related to Microsoft Teams have emerged, including those allowing attackers to recover unencrypted authentication tokens, enabling widespread identity impersonation and facilitating targeted spear-phishing operations. These incidents underscore the critical need for organisations to maintain heightened vigilance and adopt layered cyber resilience measures.

Ultimately, the Microsoft Teams vulnerabilities shine a light on a growing challenge in enterprise cybersecurity: the weaponisation of trust and collaboration tools. As these platforms become indispensable to daily operations, safeguarding them requires an integrated approach that balances technological defences with employee awareness and organisational policies. Only through this holistic strategy can businesses hope to protect the vital lines of communication that connect their teams and leadership.

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Source: Fuse Wire Services