The name Gafgyt may not bring up any connotations for most PC users. However, Gafgyt refers to an extensive network of bot computers identified by cybersecurity researchers in July 2017. The Gafgyt Botnet is based on the leaked code for the Mirai Botnet, and it is tailored to exploit the Apache Struts vulnerability (CVE-2017-5638) exposed in the Equifax Data Breach from July 2017. The Gafgyt Botnet appears to link unpatched systems in enterprise environments. Considering that enterprises pay for extra Internet bandwidth, it is beneficial to infect the hardware of high-profile companies. Hence, the bot computers would allow for more potent Distributed Denial of Service (DDoS) attacks. The malware is known to include attack models for much more than CVE-2017-5638. The Gafgyt Botnet recognizes unpatched flaws in Linksys E-Series routers; Huawei routers; video surveillance hardware from Vacron; a small number of D-Link device models; and a wide range of models of cloud cameras and DVRs.
The Gafgyt Botnet also is known under the moniker "BASHLITE" thanks to samples from infected IoT devices. The Gafgyt Botnet is one of the persistent threats to IoT setups, and it has another advantage — support for the "BlackNurse" DDoS attack method. This particular DDoS attack is dubbed the "Ultimate DDoS Attack" by some computer security bloggers due to its staggering efficiency compared to similar flooding techniques. The Gafgyt Botnet uses the "BlackNurse" DDoS attack that is based on an ICMP flooding technique. Bots sending specially crafted ICMP data packets on a limited bandwidth (approximately 20MBit/s) managed to cause "Destination Unreachable" error reports for other network users. Also, the "BlackNurse" attack proved to impact firewalls differently depending on their configurations.
You should keep your network routers up-to-date and avoid using weak login credentials for remote desktop access. Server administrators should implement adequate protection against the "BlackNurse" DDoS attack method and work with firewall manufacturers to block attack IP addresses on time. Make sure to track firmware updates from hardware manufacturers and inspect the questionable activity of accounts on your network.