Recently, a team of experts from JumpSEC Labs discovered a vulnerability in Microsoft Teams that allows malicious actors to bypass policy controls and introduce malware through external communication channels. Leaving end-users susceptible to phishing attacks.
Microsoft’s advice is to educate end-users to detect phishing attempts. One workaround would be to disable Microsoft Teams collaboration with external organizations.
This particular vulnerability in Microsoft Teams enables threat actors to bypass existing policy controls, allowing them to share links to malicious files within Teams chats, without the end-user ever accepting a message-request. This circumvention of security measures can have severe consequences for organizations, especially considering that Microsoft Teams boasts a user base of 300 million users worldwide.
To make matters worse, this attack does not rely on email, bypassing traditional email security measures and abusing the inherent trust end-users have with collaboration tools. Besides end-users, many organizations inherently trust SaaS as a reliable source as well. This translates to security controls where trusted sources are not inspected and thus bypassed.
The Netskope Threat Labs Stats for June 2023 blog revealed that 60% of all malware downloads through HTTP/HTTPS were traced back to popular cloud apps. Additionally, 32% of SaaS-delivered malware originated from OneDrive and SharePoint, indicating the need for strengthened security measures on these platforms. The notion that SaaS is considered a ”trusted source” directly contradicts the fundamental principle of zero trust.
Based on these principles, organizations should always inspect all downloads for threats, regardless of their origin. This approach allows organizations to enable external parties to share content while still leveraging Netskope Advanced Threat Protection to block malicious file transfers.
To effectively combat such threats, organizations need a comprehensive cybersecurity solution that follows the principles of zero trust and secure access service edge (SASE). Netskope implements these principles through its private cloud platform regardless of an organization’s location or the nature of their workloads (Web, SaaS, VPC, IaaS, etc.), protecting users and