During Q3 2026, attacks targeting poorly managed Linux SSH servers were observed, primarily using brute force and dictionary attacks. The main malware families involved were ShellBot, a Perl-based DDoS bot, and Fisieredoor, a backdoor capable of command execution and deploying SSH dictionary attack tools. Attackers used wget or curl to download malware, then installed user-mode rootkits, process masking tools (XHide), and XMRig cryptocurrency miners. The malware launcher used ld.so.preload to inject rootkits and disguised mining processes as legitimate bash sessions. Fisieredoor also deployed tools for credential harvesting and lateral movement, transmitting successful authentication data to command servers.
An Iranian threat actor's operational infrastructure was exposed through an open directory, revealing a 15-node relay network spanning Finland and Iran, an SSH-based botnet framework, and an active command and control server. The exposed bash history documented the full operation, including tunnel deployment, DDoS tooling development, and botnet creation. The actor used on-host compilation to evade detection and leveraged a Python script for mass SSH deployment. The botnet client, compiled and renamed 'hex' on infected hosts, showed automatic reconnection capabilities. This operation appears to be financially or personally motivated rather than state-directed, with infrastructure dual-purposed for censorship bypass and attack operations.
A sophisticated campaign targeting Russian and Belarusian military personnel has been identified, using multi-stage infection chains and decoy documents. The attackers deploy OpenSSH and Tor bridges to establish covert remote access and lateral movement capabilities. The infection process involves PowerShell scripts, scheduled tasks for persistence, and the use of Tor hidden services to expose multiple local services. The campaign employs anti-analysis techniques and leverages obfuscated configurations for SSH and Tor. While attribution remains uncertain, the targeting and tactics are consistent with Eastern European-linked espionage activities focusing on defense and government sectors.
Google Threat Intelligence Group (GTIG) is tracking BRICKSTORM malware activity, which is being used to maintain persistent access to victim organizations in the United States. Since March 2025, Mandiant Consulting has responded to intrusions across a range of industry verticals, most notably legal services, Software as a Service (SaaS) providers, Business Process Outsourcers (BPOs), and Technology. The value of these targets extends beyond typical espionage missions, potentially providing data to feed development of zero-days and establishing pivot points for broader access to downstream victims.
A recent attack on poorly managed Linux servers has been identified, involving the installation of SVF Botnet, a DDoS Bot malware developed in Python. The malware uses Discord as its C&C server and employs multiple proxy servers for DDoS attacks. The threat actor gains access through weak SSH credentials and installs the bot using specific commands. SVF Bot supports various DDoS attack methods, primarily L7 HTTP Flood and L4 UDP Flood. It uniquely utilizes public proxy addresses for HTTP flood attacks, enhancing its effectiveness. The malware can receive commands from the threat actor, turning infected Linux servers into DDoS Bots. To protect against such attacks, administrators are advised to use strong passwords, regularly update systems, and implement security measures like firewalls.
A recent incident response case in Brazil revealed a Perl-based crypto mining botnet called Outlaw, also known as Dota, targeting Linux environments. The threat actor exploits weak SSH credentials, downloads malicious scripts, and deploys an XMRig miner for Monero cryptocurrency. The botnet includes an IRC-based client that acts as a backdoor, allowing for various malicious activities. Victims have been identified mainly in the United States, with additional targets in Germany, Italy, Thailand, Singapore, Taiwan, Canada, and Brazil. The article provides detailed analysis of the malware's components, persistence mechanisms, and evasion techniques. Recommendations for system administrators include hardening SSH configurations and implementing additional security measures to mitigate the risk of compromise.
The initial access broker (IAB), whom Talos calls “ToyMaker” and assesses with medium confidence is a financially motivated threat actor, exploits vulnerable systems exposed to the internet. They deploy their custom-made backdoor we call “LAGTOY” and extract credentials from the victim enterprise. LAGTOY can be used to create reverse shells and execute commands on infected endpoints.
