Since its emergence in early 2025, the RondoDox botnet has rapidly evolved into a formidable threat, targeting a diverse array of internet-connected devices, including consumer routers, enterprise CCTV systems, and web servers. Its modular architecture enables operators to deploy specialized exploit modules against more than 50 distinct vulnerabilities, facilitating swift and widespread compromise across various platforms.
Discovery and Analysis
In April 2025, researchers at Trend Micro identified RondoDox following the detection of unusual traffic patterns originating from compromised DVR appliances across multiple regions. Subsequent analysis revealed that the botnet’s core engine is written in Go, a programming language known for its cross-platform capabilities and efficient binary size. This design choice allows RondoDox to operate seamlessly across different device architectures. Furthermore, the botnet employs encrypted communication protocols, ensuring that command-and-control (C2) exchanges remain stealthy and difficult to detect, even under rigorous network monitoring.
Infection Mechanism
The infection process of RondoDox typically begins with a reconnaissance phase, during which the malware’s scanning module probes devices for open Telnet (port 23), SSH (port 22), and HTTP management interfaces. Once a vulnerable target is identified, the botnet delivers the appropriate exploit payload from its extensive repository.
For example, one of the modules utilizes the CVE-2021-20090 vulnerability, an authentication bypass flaw in certain routers, to execute a shell payload. The exploit involves downloading a malicious script from a remote server, granting it execution permissions, and running it with administrative privileges. This script then fetches and executes the main RondoDox binary, establishing a foothold on the compromised device.
After successful exploitation, the payload establishes an encrypted TLS channel back to the C2 server on port 443, masquerading its traffic as legitimate HTTPS communication. Trend Micro analysts observed that this encryption scheme relies on a custom certificate bundle, complicating efforts to intercept and inspect the malicious traffic. Once communication is established, the bot requests and loads additional modules—such as network scanners or Distributed Denial of Service (DDoS) tools—directly into memory, enhancing its capabilities without leaving traces on the device’s storage.
Persistence and Adaptability
RondoDox employs device-specific persistence techniques to maintain control over compromised systems. On Linux-based DVRs, it may create crontab entries to ensure the malware runs at regular intervals. In certain router models, the botnet modifies firmware images to embed its components, allowing it to survive device reboots and firmware updates. This adaptability underscores the botnet’s resilience and the challenges it poses to remediation efforts.
Exploited Vulnerabilities
The table below provides a detailed overview of some of the vulnerabilities currently exploited by RondoDox, including their CVE identifiers, affected products, impact ratings, required exploit prerequisites, and CVSS 3.1 scores:
| Vendor / Product | CVE ID | CWE / Type | Status | Notes |
|—————————-|——————|——————————–|——–|——-|
| Nexxt Router Firmware | CVE-2022-44149 | CWE-78 (Command Injection) | N-Day | |
| D-Link Routers | CVE-2015-2051 | CWE-78 | N-Day | |
| Netgear R7000 / R6400 | CVE-2016-6277 | CWE-78 | N-Day | |
| Netgear (mini_httpd) | CVE-2020-27867 | CWE-78 | N-Day | |
| Apache HTTP Server | CVE-2021-41773 | CWE-22 (Path Traversal / RCE) | N-Day | |
| Apache HTTP Server | CVE-2021-42013 | CWE-22 | N-Day | |
| TBK DVRs | CVE-2024-3721 | CWE-78 | Targeted | |
| TOTOLINK (setMtknatCfg) | CVE-2025-18 | | | |
Mitigation Strategies
The emergence and rapid proliferation of RondoDox highlight the critical importance of robust cybersecurity practices. To mitigate the risks associated with this botnet, organizations and individuals should consider the following strategies:
1. Patch Management: Regularly update firmware and software to address known vulnerabilities. Timely application of patches can prevent exploitation of known flaws.
2. Network Segmentation: Implement network segmentation to limit the spread of malware within an organization. By isolating critical systems from less secure devices, the impact of a potential compromise can be minimized.
3. Access Controls: Enforce strong authentication mechanisms and restrict access to management interfaces. Disable unnecessary services and ports to reduce the attack surface.
4. Monitoring and Detection: Deploy intrusion detection and prevention systems to monitor network traffic for signs of malicious activity. Regularly review logs and alerts to identify potential compromises.
5. User Education: Educate users about the risks of IoT devices and the importance of security best practices, such as changing default passwords and recognizing phishing attempts.
By implementing these measures, organizations can enhance their resilience against botnets like RondoDox and protect their network-connected devices from compromise.
