Moobot Leverages Zero-Day Vulnerability to Target Fiber Routers

Security researchers observed Moobot and other botnets attempting to exploit a zero-day vulnerability in order to compromise fiber routers.

The Network Security Research Lab at 360 detected Moobot abusing the zero-day vulnerability beginning in late February 2020. The exploit involved two steps at the time of analysis. For it to work, digital attackers needed to leverage another vulnerability along with the zero-day flaw.

Not all threat actors who attempted to exploit the zero-day weakness realized the need for another security flaw. This fact became evident in mid-March when the Gafgyt malware tried using a Netlink GPON router remote command execution vulnerability PoC released by Exploit Database, which matched the vulnerability abused by Moobot a month earlier. Gafgyt conducted an internet-wide scan using the exploit, but because it did not leverage another vulnerability, the scan mostly failed.

The same thing happened when digital attackers attempted to spread the Fbot botnet using the flaw. Without the incorporation of another vulnerability, many of the exploit attempts failed.

A Look Back at Moobot’s Recent Activity

Security professionals with the Network Security Research Lab at 360 first came across Moobot back in September 2019. At that time, the team observed the malware using Mirai’s scanning technique to scour the internet for vulnerable devices. It was just a few months later when Network 360 reached out to the equipment manufacturer LILIN after observing multiple attack groups exploiting zero-day vulnerabilities in its DVRs to spread Moobot and other botnets.

How to Defend Against Zero-Day Vulnerabilities

Infosec personnel can help defend their organizations against zero-day vulnerabilities by checking for firmware updates that affect their routers. This process will likely involve registering their devices and signing up for email alerts. Companies should also consider deploying tools that use artificial intelligence (AI) for the purpose of detecting malicious behaviors, such as attempted exploitation of flaws that have yet to be publicly disclosed.