Security Trends·Jun 10, 2025

DDoS Attack Trends 2025: Unprecedented Growth in Scale and Complexity

An in-depth analysis of global DDoS attack data for H1 2025, revealing exponential growth in attack scale and new multi-vector attack techniques.

Hiddos Security Team

Attack Scale Reaches Record Highs

In the first half of 2025, global DDoS attacks reached record highs in both scale and frequency. According to real-time data from Hiddos's global threat monitoring network, the largest attack peak reached 3.8 Tbps, a 215% increase year-over-year. This figure not only set a new historical record but also marked DDoS attacks officially entering the "terabit era."

Key Finding: During Q1-Q2 2025, "ultra-large traffic" attack events exceeding 1 Tbps reached 237 incidents, a 180% surge year-over-year. This means that more than one Tbps-level attack occurs globally every day.

Key Data Overview

Metric	H1 2025	Year-over-Year Change
Largest attack peak	3.8 Tbps	+215%
Average attack duration	47 minutes	+32%
Attacks exceeding 1 Tbps	237 incidents	+180%
Multi-vector hybrid attacks	68%	+25%
Average attack frequency (per customer)	32 attacks/month	+45%

Attack Peak	Share	Trend
< 1 Gbps	38%	↓ Declining
1-10 Gbps	30%	→ Stable
10-100 Gbps	20%	↑ Rising
100 Gbps - 1 Tbps	9%	↑↑ Significantly rising
> 1 Tbps	3%	↑↑↑ Sharply rising

New Attack Technique Analysis

AI-Driven Intelligent Attacks

Trend Insight: The most concerning change in 2025 is that attackers have begun systematically leveraging AI technology to optimize attack strategies. Through machine learning models that automatically adjust attack traffic patterns, traditional threshold-based detection systems find it harder to identify threats.

AI-powered attacks exhibit three major characteristics:

Adaptive traffic patterns: Attack traffic can mimic normal user behavior, dynamically adjusting request frequency and content
Multi-vector coordination: AI orchestrators simultaneously schedule multiple attack vectors, launching attacks at different layers
Intelligent timing selection: By analyzing target business patterns, choosing the most vulnerable time windows to launch attacks

Surge in Application-Layer Attacks

L7 application-layer attacks grew 156% year-over-year, becoming a threat source as significant as network-layer attacks.

HTTP/2 Rapid Reset Variants

Exploits HTTP/2 protocol stream multiplexing to rapidly send and reset requests, causing server resource exhaustion. 2025 variants add connection-layer obfuscation, further increasing detection difficulty.

HTTP/2 Continuation Flood

Sends massive HTTP/2 CONTINUATION frames to exhaust the server's header parsing buffer. This attack method was widely exploited in Q2 2025.

WebSocket Flood

Leverages WebSocket persistent connections to establish massive numbers of long-lived connections before sending enormous data volumes, bypassing traditional HTTP request rate limits.

Multi-Vector Hybrid Attacks

In 2025, 68% of DDoS attacks simultaneously included two or more attack vectors. By combining L3/L4 network-layer attacks with L7 application-layer attacks, attackers force protection systems to respond across multiple dimensions simultaneously, greatly increasing defense difficulty.

Typical hybrid attack patterns include:

Preemptive strike: First use large-volume UDP Flood to consume bandwidth, then HTTP Flood to attack the application layer
Diversionary tactics: Use SYN Flood to attract protection attention while simultaneously using Slowloris to exhaust the connection pool
Sustained pressure: Long-duration low-intensity attacks combined with intermittent high-intensity pulses to test the limits of protection systems

Protection Recommendations

Deploy Full-Layer Protection

Combine L3/L4/L7 full-layer protection to ensure each OSI layer has corresponding detection and scrubbing capabilities. The Hiddos platform provides an integrated protection solution from the network layer to the application layer.

Enable AI Detection Engine

Leverage machine learning to identify new attack patterns, especially against AI-driven adaptive attacks. Hiddos's AI engine can complete detection and response within 3 seconds of an attack occurring.

Establish Incident Response Plans

Build detailed DDoS incident response procedures with clear responsibilities and operational steps for each stage. Conduct regular attack-defense drills to ensure plan executability.

Regular Stress Testing

Evaluate the actual effectiveness of protection capabilities through simulated attacks, identifying and fixing protection blind spots. Hiddos provides professional stress testing services.

Hiddos Protection Capabilities

The Hiddos platform successfully mitigated all attacks in H1 2025, with customer service availability reaching 99.997%. Through the global distributed Anycast network, attack traffic is automatically dispersed to the nearest scrubbing nodes, ensuring normal business operations are unaffected.

Hiddos Advantages: 68 global protection nodes, Tbps-level scrubbing capacity, AI-driven second-level detection and response, 24/7 security expert team support.

Outlook

As AI technology continues to deepen its application on both offense and defense, DDoS attacks will continue to evolve in the second half of 2025. Enterprises need to shift from "passive defense" to "active protection," building intelligent defense systems with AI at their core, in order to maintain business continuity in an increasingly severe security landscape.

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