Cyber attackers are employing a novel phishing technique, exploiting Microsoft Teams group chat requests to disseminate DarkGate malware. In a sophisticated operation, over 1,000 malicious Teams group chat invitations were sent, using seemingly compromised Teams user accounts. Once victims accept the chat request, they are tricked into downloading a file named ‘Navigating Future Changes October 2023.pdf.msi,’ a common DarkGate tactic. Following installation, the malware establishes communication with its command-and-control server, posing a significant threat to organizations.
This phishing campaign takes advantage of Microsoft Teams’ default setting that allows external users to message other tenants, making it crucial for organizations to assess and potentially disable such external access. AT&T Cybersecurity researchers emphasized the need for heightened user awareness, urging caution regarding unsolicited messages and the varied forms phishing attacks can take. Microsoft Teams, with its massive user base of 280 million monthly users, has become an attractive target for threat actors seeking to exploit the platform’s vulnerabilities. The DarkGate malware, known for its capabilities and resurgence after disruptions to the Qakbot botnet, highlights the evolving landscape of cyber threats in collaboration platforms.
As DarkGate gains prominence, it has been observed that cybercriminals are increasingly turning to this malware loader as a preferred means of gaining initial access to corporate networks. The surge in DarkGate infections follows the disruption of the Qakbot botnet and the subsequent attempts by the malware’s developer to sell annual subscriptions. The DarkGate malware includes various capabilities, such as a concealed VNC, tools to bypass Windows Defender, a browser history theft tool, an integrated reverse proxy, a file manager, and a Discord token stealer. This wave of attacks emphasizes the critical importance of securing collaboration platforms and staying vigilant against evolving cyber threats.
In the wake of the international effort that disrupted the Qakbot botnet, cybercriminals have increasingly embraced DarkGate as their preferred method for initial access to corporate networks. After the Qakbot botnet takedown, the DarkGate malware loader has gained notoriety, with cybercriminals employing various delivery methods, including phishing and malvertising. The surge in DarkGate infections is particularly notable, underscoring the heightened risk organizations face from sophisticated cyber threats.