A recently discovered DDoS botnet is enslaving multiple router models and various types of web servers by abusing known vulnerabilities, researchers at Fortinet Labs warned.
Dubbed Enemybot, the botnet has been linked to the cybercrime group named Keksec which specializes in DDoS attacks and cryptocurrency mining and has been linked to multiple botnets such as Simps, Ryuk, and, Samel.
The malware is the result of combining and modifying the source code of the Gafgyt (Bashlite) botnet – which leaked in 2015 –and the infamous Mirai botnet, with the latest version using the scanner module and a bot killer module.
Enemybot employs multiple obfuscation methodologies meant not only to prevent analysis, but also to keep it concealed from other botnets, and connect to a remote server that's hosted in the Tor anonymity network to fetch attack commands.
The new botnet also attempts to exploit a wide range of devices and architectures by using known combinations of usernames and passwords, running shell commands on Android devices with a compromised Android Debug Bridge port (5555), and targeting roughly 20 known router vulnerabilities.
The most recent of the targeted security loopholes is CVE-2022-27226, a remote code execution issue that impacts iRZ mobile routers, and which was made public on March 19, 2022. Enemybot, Fortinet points out, is the first botnet to target devices from this vendor.
Enemybot also targets the now infamous Apache Log4j remote code execution vulnerabilities disclosed last year (CVE-2021-44228 and CVE-2021-45046), as well as a couple of path traversal issues in the Apache HTTP server (CVE-2021-41773 and CVE-2021-42013).
The botnet also attempts to abuse security loopholes in TOTOLINK routers and Seowon routers, as well as older vulnerabilities in ThinkPHP, D-Link routers, NETGEAR products, Zhone routers, and ZyXEL devices.
Once a flaw has been successfully abused, the malware runs a shell command to download a shell script from a URL that is dynamically updated by the C&C. The script is responsible for downloading the actual Enemybot binary compiled for the target device’s architecture.
After successful exploitation, the malware links to its C&C server and waits for further instructions. Based on received commands, it can perform DNS amplification attacks and various types of DDoS assaults, sniff traffic, and spread to other devices via brute force attacks.
“This mix of exploits targeting web servers and applications beyond the usual IoT devices, coupled with the wide range of supported architectures, might be a sign of Keksec testing the viability of expanding the botnet beyond low-resource IoT devices for more than just DDoS attacks. Based on their previous botnet operations, using them for crypto mining is a big possibility,” Fortinet notes.
