Summary: A highly sophisticated campaign is distributing the new “DarkGate 2.0” loader via Microsoft Teams. Attackers are using compromised external tenant accounts to send chat invites to corporate users. The lure involves a file named “Navigating Future Changes 2026.pdf.msi,” which installs a stealthy backdoor capable of bypassing Windows Defender.
Business Impact: This attack bypasses traditional email filters entirely. Employees often trust Teams messages more than email, leading to higher click rates. The malware provides “Access-as-a-Service” to ransomware groups, posing an immediate extortion risk.
Why It Happened: Many organizations still have “External Access” enabled in Teams by default, allowing any external Microsoft 365 user to initiate a chat. Attackers have automated the process of spinning up disposable tenants to launch these attacks at scale.
Recommended Executive Action: Review your Microsoft Teams admin settings immediately. Restrict “External Access” to only trusted domains (Allow-listing) or disable it entirely if not critical for business operations. Conduct a quick “Phishing Drill” using this specific Teams vector.
Hashtags: #DarkGate #MicrosoftTeams #Malware #SocialEngineering #Phishing #CyberDefense