A new and perilous strain of malware named SkidMap has emerged, specifically designed to exploit vulnerabilities in Redis services, targeting a broad spectrum of Linux distributions.
According to Trustwave security researcher Radoslaw Zdonczyk, this malware demonstrates adaptability by customizing its actions based on the system it infects. Linux distributions such as Alibaba, CentOS, RedHat, and more are within SkidMap’s scope. This malware, initially identified by Trend Micro in 2019 as a cryptocurrency mining botnet, can obscure its activities and monitor mining processes using malicious kernel modules.
The operators behind SkidMap have taken a sophisticated approach by concealing their command-and-control (C2) IP address on the Bitcoin blockchain, mirroring a tactic seen in the Glupteba botnet. The strategy of sourcing real-time data from a decentralized and uncensorable data source makes tracking and pivoting the C2 IP address a complex endeavor. Trustwave’s recent analysis reveals an attack chain where vulnerable Redis server instances are exploited to deploy a dropper shell script, distributing an ELF binary disguised as a GIF image file. This binary then adds SSH keys, disables SELinux, and establishes a reverse shell, culminating in the download of a specific package based on the Linux distribution and kernel.
The package includes shell scripts for kernel module installation, obfuscating logs, and launching a botnet component for retrieving rootkit payloads. The malware’s advanced nature poses significant detection challenges, especially in large server infrastructures.
Trustwave’s Zdonczyk highlighted that even on home computers, the only noticeable signs of compromise were unusually loud fans and elevated laptop temperatures. SkidMap’s versatility and potential impact underscore the importance of robust cybersecurity measures to safeguard against its threats.
