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Microsoft Azure Neutralizes the Largest DDoS Attack in History
Microsoft Azure has successfully mitigated a record-breaking 15.72 terabits per second (Tbps) distributed denial-of-service (DDoS) attack, the largest ever recorded, targeting a single cloud endpoint in Australia. According to Microsoft’s official disclosure, the attack also peaked at 3.64 billion packets per second (pps) — a volume designed to overwhelm cloud defenses in seconds.
SquaredTech breaks down how Azure stopped it, what made this attack so massive, and what it means for enterprises facing increasingly aggressive cyber threats.
Read more on our article of, Microsoft Just Paid $135 Billion to Put a Collar on AGI, published on November 4 2025, SquaredTech.
The Scale and Nature of the 15.72 Tbps Attack
Microsoft confirmed the attack, which occurred on October 24, 2025, originated from a 500,000-device IoT botnet, tied to the Aisuru malware family. The traffic came from a global distribution of compromised smart cameras, DVRs, Wi-Fi routers, and other high-bandwidth IoT devices that attackers weaponized into a single, coordinated wave.
To put 15.72 Tbps in perspective:
- It’s equivalent to 3.5 million people streaming Netflix at once.
- The attack used a multi-vector strategy, combining UDP flood traffic, TCP SYN and ACK floods, DNS reflection, and other amplification techniques.
This aligns with the newest pattern seen in 2025 attacks: “hit-and-run” DDoS bursts—extremely intense traffic spikes that last only seconds but deliver enough power to overwhelm unprepared systems.
This attack dwarfed earlier 2025 cloud records, including:
- 7.3 Tbps attack (June 2025, Cloudflare)
- 11.5 Tbps attack (September 2025, Cloudflare)
The fact that attackers nearly doubled these cloud-focused volumes in a matter of months shows a rapid evolution in botnet size, cloud bandwidth abuse, and available attack tools.
How Microsoft Azure Mitigated the Attack
Microsoft reports that Azure DDoS Protection:
- Detected the attack instantly
- Applied automated rate-limiting per protocol
- Used adaptive real-time tuning
- Filtered malicious traffic through global edge scrubbing centers
- Maintained service availability with zero customer impact
Azure’s mitigation involved analyzing signature patterns and anomalies, then adjusting filtering thresholds in real time. Microsoft notes that legitimate traffic remained unaffected, demonstrating that their cloud-native mitigation pipelines can absorb massive volumetric attacks without service interruption.
Azure’s ability to neutralize 15.72 Tbps without customer downtime reinforces the importance of integrated cloud defenses, especially as attacks increasingly bypass traditional appliance-based solutions.
Rising Threats from IoT and Global Bandwidth Expansion
The explosion of IoT devices—now exceeding 17 billion globally—has created a vast and poorly secured attack surface. Many devices include:
- High-speed network capabilities (leveraging fiber-to-the-home speeds)
- Infrequent firmware updates
- Weak default authentication
- Limited logging
This creates an ecosystem where attackers can silently enroll devices into botnets without owners noticing. The Aisuru botnet, responsible for this attack, is a ‘Turbo Mirai-class’ botnet that exploits these vulnerabilities, primarily targeting compromised home routers and cameras. Cloudflare reports that over 70% of volumetric DDoS attacks in 2025 originated from IoT-powered botnets.
Security analyst Sunil Varkey describes this as a “global cyber hygiene failure.” Infected IoT networks continue to grow, making future attacks even more intense.
What This Means for Enterprises and Cloud Users
While Azure mitigated this attack with no customer impact, the event carries serious implications for businesses:
- Service availability: Applications running on unprotected infrastructure remain vulnerable.
- Cost risks: Unmitigated attacks may cause bandwidth spikes and infrastructure exhaustion.
- Regulatory pressure: Industries increasingly must demonstrate resilience against cyber disruptions.
- Multi-cloud exposure: Attackers target cloud providers sequentially—not individually.
- Supply chain risk: Even a short DDoS event can disrupt APIs, SaaS dependencies, or authentication flows.
Enterprises can no longer rely on traditional network firewalls or on-prem mitigation. Ultra-high-volume attacks require cloud-native defenses with global distribution.
Recommendations for Preventing Future DDoS Incidents
We emphasize that enterprises must adopt layered security defenses to protect against growing DDoS threats. Effective strategies include:
- Traffic-rate Limiters: Control maximum requests allowed per source, reducing exposure to flood patterns.
- DDoS Scrubbing Services: Use cloud-based scrubbing tunnels to filter malicious packets in real time.
- Network Stress Testing: Simulate large bursts to identify bottlenecks.
- Zero-Trust Networking for IoT: Authenticate every device and isolate untrusted segments.
- Regular Firmware and Patch Maintenance: Keep IoT devices updated to reduce hijacking potential.
- Deploy Cloud-Native DDoS Protection (Azure/Cloudflare/AWS): Hyperscalers handle volumetric bursts better than on-prem appliances.
These practices help organizations detect and mitigate attacks early, preventing potential downtime or data compromise.
The Never-Ending Cybersecurity Challenge
The Azure incident highlights a key trend: as cloud defenses improve, attackers scale up their botnets.
While Azure mitigated its attack successfully, the broader industry shows the challenge:
- Cloudflare recently disclosed mitigating an even larger attack—22.2 Tbps—linked to a similar botnet family in September 2025, which targeted a gaming infrastructure company.
- AWS disclosed a multi-vector burst attack earlier in 2025, demonstrating the shared threat.
Global internet traffic reports indicate DDoS activity is growing at triple-digit percentages year-over-year. It’s an escalating arms race—one where cloud providers and enterprises must constantly adapt.
Conclusion
The 15.72 Tbps DDoS attack on Microsoft Azure marks a turning point in cloud cyber warfare. It demonstrates the sheer scale of modern attacks powered by IoT devices, high-speed home networks, and evolving botnet families like Aisuru.
Azure’s successful mitigation highlights the importance of cloud-native, globally distributed defenses. But it also underscores the need for shared responsibility between manufacturers, operators, and end-users to address the root cause: IoT vulnerabilities.
SquaredTech will continue monitoring developments in cloud security, DDoS trends, and mitigation technologies as cyber threats evolve.
For more Updates: TechNews
