Cyberattacks increased this year, leading to more than 25 record-breaking distributed denial-of-service (DDoS) incidents while AI bots increased activity, Cloudflare’s yearly review showed.

In its sixth annual 2025 Year in Review, Cloudflare revealed the key findings and observations across the top internet services, with network-layer DDoS attacks peaking at 31 Tb/s in 2025.

The company itself became the center of attention this year due to global outages in November, a result of a change to permissions in one of its database systems. Cloudflare was then affected by another shorter-lived outage this month, which saw platforms including Substack, Canva, and X (formerly Twitter) taken down.

The report showed that nearly half of the outages observed this year were caused by government activities like the internet shutdown in Tanzania in response to election day protests; outages in Jamaica around Hurricane Melissa; and some countries trying to prevent students from cheating on academic exams, such as Iraq, Syria, and Sudan.

Still, another recent Cloudflare report, published in December, found 8.3 million DDoS attacks in the last quarter, a 40% year-over-year increase in threats to networks.

Cloudflare’s quarterly threat report found a 15% sequential increase in attacks, equivalent to nearly 3,780 attacks per hour, and corresponding to 170% of the DDoS attacks mitigated by Cloudflare throughout last year.

“The internet isn't just changing, it's being fundamentally rewired," Cloudflare CEO Matthew Prince explained. "From AI, to more creative and sophisticated threat actors, every day is different. While we celebrated several Internet milestones this year, we also blocked attacks that redefined what 'scale' means, and witnessed the traditional business model of online content creation face stark challenges.

“With a huge percentage of the internet running through Cloudflare’s network every second of every day, we believe we have a unique responsibility to help navigate these changes and build a better internet for everyone,” he added.

AI and bot traffic

AI dominated much of the news this year, as the rapidly evolving scene saw generative AI providers regularly release more powerful models capable of tasks such as text and image generation, speech recognition, and image classification.

AI use was also tied to the 19% year-over-year jump in global internet traffic, the review highlighted, as more advanced capabilities are introduced to AI.

Among the generative AI services, OpenAI’s ChatGPT kept its position at the top of the list. But the dynamic nature of the industry showed elsewhere as services like Perplexity, Claude/Anthropic, and GitHub Copilot moved up to a third, second and sixth position, respectively. New names in the top 10 list for 2025 were Google Gemini, Windsurf AI, Grok/xAI, and DeepSeek.

AI bots also became more prominent, taking up 4.2% of HTML request traffic as they trawled the web for content used in training models. The report showed that the highest bot traffic over a quarter came from Googlebot, which trawls for both search engine indexing and AI training.

Amid this trend, Cloudflare proposed some responsible AI bot principles, such as companies publicly disclosing information about their AI bots, and these having one openly declared purpose.