A sudden and overwhelming flood of web traffic can bring even the most robust online services to a grinding halt, but what if that traffic looked entirely legitimate? A newly identified malware botnet, dubbed “Udados,” is leveraging this very tactic to execute large-scale HTTP flood Distributed Denial-of-Service (DDoS) attacks with devastating efficiency. The primary targets of these sophisticated campaigns have been organizations within the Technology and Telecommunications sectors, where continuous uptime is paramount. The core objective of the Udados botnet is not just disruption, but a calculated effort to cripple business operations by inundating servers with a high volume of web requests that are meticulously crafted to mimic genuine user activity. This deceptive approach makes traditional detection and mitigation strategies significantly more difficult for network defenders, allowing the attack to persist and cause maximum damage before its true nature is uncovered.
Anatomy of an Attack
The operational sophistication of the Udados malware begins the moment a host is compromised, at which point it quietly establishes a persistent connection with a remote Command and Control (C2) server. Rather than immediately launching an attack, the infected device enters a dormant state, awaiting specific directives from the botnet operator. During this waiting period, the malware diligently gathers and transmits detailed system telemetry back to its C2 hub. This information is sent in a structured JSON data format, providing the operator with a comprehensive overview of their compromised assets. Key metadata points include a unique user ID (Uid), the current task status (St), the specific bot version (Bv), and the privilege level (Priv) of the malware on the infected system. This constant stream of data enables the botnet controller to manage their network of bots with remarkable efficiency, categorizing them based on capability and ensuring that attack commands are sent to the most suitable devices for the intended target.
When the command to strike is given, the C2 server issues a specific directive that activates the botnet’s primary weapon. The most frequently observed command is !httppost, a directive that awakens the DDoS module within the malware. This command is not a simple “on” switch; it includes a set of precise parameters that define the assault’s characteristics. These parameters dictate the total duration of the attack, the number of concurrent threads the bot should use to generate traffic, and a Base64-encoded payload of random data to be included in the requests. By strategically employing HTTP POST requests, which are commonly used for submitting form data on websites, the malicious traffic effectively blends in with the flow of normal user activity. This camouflage is the botnet’s greatest strength, as it complicates the efforts of automated defense systems and human analysts who must distinguish between legitimate and malicious requests, often in real-time, to prevent a complete service outage.
Tracing the Infrastructure and Identifying Threats
The resilience and operational security of the Udados botnet are significantly bolstered by its carefully chosen infrastructure. Investigations have traced its C2 server to the IP address 178.16.54[.]87, which is hosted within Autonomous System AS214943. This entity, known commercially as RAILNET, has unfortunately developed a notorious reputation within the cybersecurity community as a sanctuary for malicious operations. It functions as a “bulletproof” hosting provider, offering services to threat actors with minimal oversight. Intelligence reports from late 2025 revealed that RAILNET’s infrastructure was a hub for illicit activity, hosting C2 servers for over 30 distinct malware families. This rogue’s gallery includes prominent and persistent threats such as the Remcos remote access trojan and the Amadey botnet, placing Udados in the company of some of the most active malware in the digital landscape. This concentration of malicious actors within a single network provider highlights the challenges defenders face in disrupting these operations at their source.
Given the clear and present danger posed by this threat, immediate and decisive defensive measures were essential. Organizations were strongly advised to implement a multi-layered defense strategy, starting with blocking all inbound and outbound traffic to and from the identified C2 infrastructure, particularly the IP address 178.16.54[.]87 and the associated domain ryxuz[.]com. Active network monitoring for specific indicators of compromise (IOCs) proved to be the most effective proactive measure. Key digital fingerprints for detection included two specific SHA256 file hashes: 7e2350cda89ffedc7bd060962533ff1591424cd2aa19cd0bef219ebd576566bb and 770d78f34395c72191c8b865c08b08908dff6ac572ade06396d175530b0403b8. Furthermore, network administrators learned to inspect outbound HTTP traffic for the specific communication URI path /uda/ph.php and the presence of JSON parameters like uid, st, msg, and tid in the request body. A sudden, short-term spike in outbound HTTP POST requests from a single host became a critical early warning sign of an impending high-volume attack, allowing for swift containment.