The provided information concerns an OSINT (Open Source Intelligence) analysis of an IRC-based botnet, specifically linked to the 'tsunami' malware family. IRC (Internet Relay Chat) botnets are a type of botnet that use IRC channels as command and control (C2) infrastructure to coordinate compromised hosts. The 'tsunami' botnet is known for its capability to conduct distributed denial-of-service (DDoS) attacks, particularly flooding attacks that overwhelm targeted systems or networks, impacting their availability. This analysis, published by CIRCL in April 2019, categorizes the threat as a campaign with a low severity rating and a moderate certainty level (50%). The botnet operates perpetually, indicating ongoing activity or persistent threat presence. The technical details suggest a moderate threat level (3 out of an unspecified scale) and a moderate analysis confidence (2 out of an unspecified scale). No specific affected versions or patches are listed, and there are no known exploits in the wild beyond the botnet's operational activity. The absence of specific indicators or CWEs limits detailed technical dissection, but the association with DDoS flooding attacks highlights the primary risk vector: availability disruption through volumetric network attacks. The IRC-based control mechanism implies that the botnet can be resilient and flexible, as IRC infrastructure is relatively simple to deploy and can be obscured or migrated to evade takedown efforts. Overall, this threat represents a persistent, low-severity risk primarily focused on availability disruption via DDoS attacks orchestrated through IRC-based botnet infrastructure.

For European organizations, the primary impact of this IRC-based tsunami botnet is the risk of availability disruption due to DDoS flooding attacks. Such attacks can degrade or completely block access to critical online services, impacting business continuity, customer trust, and operational efficiency. Sectors with high online presence such as financial services, e-commerce, telecommunications, and government services are particularly vulnerable. The low severity rating suggests that the botnet's current capabilities or scale may not be sufficient to cause widespread or highly damaging outages; however, even low-severity DDoS attacks can cause localized disruptions and incur mitigation costs. Additionally, the persistent nature of the botnet means that organizations may face repeated or ongoing attack attempts, requiring sustained defensive measures. The IRC-based command and control infrastructure also poses challenges for detection and mitigation, as IRC traffic can be encrypted or obfuscated, complicating network monitoring efforts. European organizations with limited DDoS protection or those relying on legacy network infrastructure may be disproportionately affected. Furthermore, the botnet's flooding attacks could be leveraged as a smokescreen for other malicious activities, increasing the overall risk profile.

To mitigate the threat posed by this IRC-based tsunami botnet, European organizations should implement a multi-layered defense strategy focused on detection, prevention, and response. Specific recommendations include: 1) Deploy advanced network traffic analysis tools capable of identifying IRC traffic anomalies and volumetric flooding patterns, including encrypted IRC traffic detection. 2) Implement robust DDoS mitigation solutions such as on-premises scrubbing appliances combined with cloud-based DDoS protection services that can absorb and filter large-scale flooding attacks. 3) Enforce strict egress and ingress filtering to block unauthorized IRC traffic at network boundaries, reducing the risk of botnet command and control communication. 4) Maintain updated threat intelligence feeds and collaborate with CERTs and ISACs to stay informed about emerging botnet indicators and tactics. 5) Conduct regular incident response drills simulating DDoS scenarios to ensure operational readiness. 6) Harden endpoints and servers to prevent initial compromise that could lead to botnet recruitment, including patch management and endpoint detection and response (EDR) solutions. 7) Monitor network logs for unusual connection patterns to IRC servers and promptly investigate suspicious activities. These measures, tailored to the specific threat characteristics of IRC-based botnets, will enhance resilience against availability disruptions caused by flooding attacks.