WAF

WAF (Web Application Firewall) operates at layer 7 (the application layer) of the OSI model and is capable of deep parsing of HTTP/HTTPS traffic.

Under default configurations, many CDNs/WAFs place known AI crawlers into a recognized bot category and apply a challenge (returning 403, 429 or a JS challenge page) rather than letting them through directly.

At the CDN/WAF edge layer, known malicious paths should be blocked (such as `/.env`, `/.git/`, `wp-login.php`, `xmlrpc.php`, `/proc/self/`, `..;/`, or paths ending in `service-account.json`), but substring matches must always be tested with real URLs first to avoid mistakenly blocking legitimate pages.

A CDN distributes static and cacheable content to nodes around the world, so user requests are answered nearby and the origin therefore does not see most of the traffic; a WAF performs rule matching on requests at the nodes, and can allow, challenge, rate-limit or block based on conditions such as path, method, request headers, User-Agent and IP reputation.

Rotating only proxy IPs while keeping the same User-Agent and header set forms a stable fingerprint on the WAF side, and once that fingerprint is flagged, all IPs using it are implicated.

WAF judgment is based on accumulated IP reputation; once a single residential IP is blacklisted, it will most likely not recover in the short term.

WAFs typically do not return a direct 403 for crawler traffic, but instead deliver challenge pages such as JS Challenge, CAPTCHA, and Turnstile, causing clients to continuously hit 503 or 429.

Business logic vulnerabilities cannot be identified by general-purpose security devices such as WAFs, because WAFs rely on matching known attack signatures, while the requests involved in logic vulnerabilities are completely legitimate at the syntactic level.

When a port scan detects that the target has port 3306 (MySQL's default port) open, it is flagged as a risk; however, the port may actually be unreachable from the external network due to access control whitelists, WAF, or cloud security group rules, resulting in a false positive.

Blindly injecting large numbers of payloads will trigger WAFs and cause the IP to be blocked, making it impossible to detect vulnerabilities even if they exist in the target.

CSL-Core's design philosophy of 'shadow-run first, then enforce' is similar to the detection/blocking mode switching of a WAF.

Traditional security infrastructure such as firewalls and WAFs typically adopts a Fail Closed strategy.

A growing number of websites are deploying active defense measures at the application layer (such as WAF and CDN rate limiting), rather than relying solely on declarative constraints at the protocol layer.

Traditional security protections are deployed at the gateway or WAF layer, but AI agent behaviors are dynamically generated, and by the time traffic reaches the gateway, many risk decisions can no longer be intercepted.

The main sites of large companies typically deploy WAFs, CDNs to hide real IPs, and dedicated security teams for continuous monitoring, and common vulnerabilities have been repeatedly audited and removed, making exploitation highly difficult.

A WAF can serve as one layer in a defense-in-depth strategy, but should not be relied upon as the sole barrier.

The AI penetration testing demonstrations were all conducted on publicly available target ranges; the complexity of real environments and protective mechanisms such as WAFs, honeypots, and IDS far exceed those of target ranges, and the AI's high success rate may not transfer to real business systems.

WAFs filter malicious requests through rule matching, honeypots lure attackers by simulating high-value assets, and IDS continuously analyzes network traffic to trigger alerts or automatically block anomalous behavior.

Excessively fast directory scanning speeds may trigger the target website's WAF or rate limiting, resulting in IP blocking.

Integrating CDN and WAF (such as Cloudflare) to absorb and filter malicious traffic via edge networks is currently the most mainstream first line of defense against DDoS attacks.