The Quad7 botnet is significantly expanding its operational scope by targeting a wider array of SOHO devices, including Zyxel VPN appliances, Ruckus wireless routers, and Axentra media servers. This escalation follows earlier reports of attacks on TP-Link routers and ASUS devices. The botnet’s custom malware now targets these new devices, marking a notable evolution in its attack methods. The expanded targeting aims to exploit vulnerabilities in these devices to further its control and potentially launch distributed brute-force attacks on various platforms.
Recent analysis by Sekoia highlights a shift in Quad7’s tactics. The botnet has moved away from using SOCKS proxies, which were previously instrumental in relaying malicious traffic, and has adopted more sophisticated evasion techniques. Specifically, the Quad7 operators are now utilizing the KCP communication protocol and a new tool named ‘FsyNet’ that communicates over UDP, making it more challenging to detect and track the malicious activities. This change reflects the botnet’s efforts to enhance its stealth and operational effectiveness.
The latest findings reveal that Quad7 has also introduced new backdoors and reverse shells to facilitate remote control of infected devices without exposing easily discoverable login interfaces. The new backdoor, known as ‘UPDTAE,’ establishes HTTP reverse shells, allowing the botnet operators to maintain control more discreetly. Additionally, there is experimentation with a new binary called ‘netd’ that uses the darknet-like protocol CJD route2, indicating a potential move towards even more covert communication methods.
To protect against such evolving threats, users are advised to keep their devices updated with the latest firmware, change default admin credentials to strong passwords, and disable unnecessary web admin portals. For devices no longer receiving security updates, upgrading to newer models with ongoing support is highly recommended. As Quad7 continues to adapt and expand its methods, proactive security measures are crucial in mitigating the risk posed by this increasingly sophisticated botnet.
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