Researchers at ESET have discovered an improved version of Kaiten, an Internet Relay Chat (IRC)-controlled malware typically used to carry out distributed denial-of-service (DDoS) attacks.
The digital security firm says the latest version targets embedded systems such as routers, gateways and wireless access points.
The remastered malware has been dubbed “KTN-Remastered” or “KTN-RM”, with three versions of Linux/Remaiten already identified by ESET researchers. Based on artifacts in the code, the main feature of the malware is an improved spreading mechanism.
Based primarily on Linux/Gafgyt’s telnet scanning, KTN-RM improves on that spreading mechanism by carrying downloader executable binaries for embedded platforms such as routers and other connected devices, ESET says, targeting mainly those with weak login credentials.
According to ESET, Linux/Remaiten improves upon this spreading mechanism by carrying downloader executables for CPU architectures that are commonly used in embedded Linux devices such as ARM and MIPS.
After logging on via the telnet prompt of the victim‘s device, it tries to determine the new victim‘s device platform and transfer only the appropriate downloader. This downloader’s job is to request the architecture-appropriate Linux/Remaiten bot binary from the bot’s C&C server. This binary is then executed on the new victim‘s device, creating another bot for the malicious operators to use.
“The downloader‘s job is to request the Linux/Remaiten bot binary from the Command & Control server for its current architecture. When executed, it also creates another bot for the malicious operators to use. We have seen this technique used before by Linux/Moose to spread infections,“ explains Michal Malík, ESET malware researcher.
In a strange twist, this strain of malware also has a message for those who might try to neutralise its threat, Malík says.
"Within the welcome message, version 2.0 seems to single out malwaremustdie.org which has published extensive details about Gafgyt, Tsunami and other members of this family of malware," he explains.
How to prevent and protect against this threat: