Bot Abuse Is No Longer Just a Nuisance
The term “bot” carries very different meanings depending on who you ask. A decade ago, bots were largely associated with helpful tools—managing chat rooms or enabling playful interactions in messaging platforms. Today, in the context of web security, the connotation is almost uniformly negative. A bot, at its core, is simply automated software replacing manual human action, and that automation can be scaled for both constructive and destructive ends. Search engine crawlers are a prime example of beneficial scale; credential stuffing, inventory hoarding, and Layer 7 DDoS attacks are the malicious counterparts.
The recent global microchip shortage has amplified the problem. High-demand, low-supply launches—from Microsoft, Nvidia, and Sony—have created a fertile environment for bot-driven abuse. Automated scripts scrape inventory and complete purchases far faster than any human, frustrating legitimate buyers and sometimes overwhelming applications entirely. Nvidia was famously forced to retroactively cancel bot purchases during a GPU release, and similar tactics have impacted even vaccine distribution efforts. What might start as a nuisance can quickly escalate into a significant Layer 7 DDoS attack, compounding the original problem.
Deploying Bot Management on cloudflare.com
Cloudflare’s current Bot Management product, launched in 2019, came from an internal experiment: predicting whether a request would solve a challenge using network data and machine learning models. That experiment proved robust enough to become a full-fledged security product, but the real-world validation came when the team turned the tools on their own properties. Attackers were flooding forms on Cloudflare landing pages with junk data, abusing event registrations, sales inquiries, and other lead-generation channels. The volume grew until it overwhelmed the backend form processor and clogged the CRM, turning a nuisance into an application-level DDoS scenario that required careful mitigation to avoid blocking legitimate submissions.
Early attacks were unsophisticated—obvious User Agent strings and little effort to distribute across IPs or ASNs. As Cloudflare tuned heuristics and retrained models, attackers adapted. The full armory of bot-fighting tools became necessary. In one recent incident, automated traffic spiked to seven times normal levels for about 30 minutes. Cloudflare’s Anomaly Detection system carried the load here, accounting for 42% of the detections and preventing the attack from overwhelming the downstream provider.
The internal battle extends well beyond forms. Malicious actors regularly sign up numerous domains across free top-level domains to create thousands of hostname records, a tactic used for SEO spam—crosslinking sites to artificially boost search rankings. This creates two genuine infrastructure problems for Cloudflare. First, creating a large number of domains and records simultaneously can slow down the system that pushes DNS records to 200+ locations in seconds. Second, there is the real storage cost of hosting meaningless data across the edge network. Since this attack only works at scale, the attackers need signups to be highly automated. Bot Management was deployed to challenge new account signups that showed signs of automation; the problem disappeared immediately.
The billing system has been another target. Attackers use payment card processing to test stolen numbers—validating them for resale or use elsewhere. Speed and scale return as the critical factors. Cloudflare’s billing engineering team uses Bot Management to challenge or block attempts to add or change payment methods. The bot score is also passed to the third-party payment provider’s fraud detection via Cloudflare Workers, influencing its manual review decisions.
Data at Global Scale Powers Defense
Bot Management at Cloudflare is not just a set of heuristics; it is a data problem. With roughly 25 million internet properties on the network, there is an enormous volume of traffic signals to interpret. The recent release of Super Bot Fight Mode extends bot-fighting capabilities to Pro and Business plans, which brings an additional benefit for all existing customers: as more zones block and challenge based on direct bot signals, the resulting data improves the machine learning models more directly than the inferred data used for unrelated security challenges.
Early access feedback from Enterprise customers on the API abuse detection models is narrowing the focus on a different front. APIs present distinct challenges from web-facing properties, but Cloudflare’s experience building Anomaly Detection for Bot Management translates well—related techniques can identify API endpoints and detect anomalies within automated traffic. The broader intent is to give customers a flexible security toolkit on a single platform: blocking definite attacks, challenging likely bots, and applying rate limiting to suspicious API traffic, regardless of what kind of traffic the domain receives.
