CyberRota Analysis
AI-GeneratedThe Caddy Defender plugin is vulnerable in versions prior to 0.10.1, allowing clients from blocked IP ranges to bypass request blocking when Caddy is deployed behind trusted proxies, CDNs, or load balancers. This occurs because Defender incorrectly uses the immediate peer's IP address instead of the original client's IP, potentially exposing sensitive services to unwanted access. Organizations utilizing Caddy Defender in such configurations should prioritize upgrading to version 0.10.1 or implement IP blocking at their proxy or firewall layers to mitigate this risk.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
The Caddy Defender plugin is a middleware for Caddy that allows users to block or manipulate requests based on the client's IP address. Prior to version 0.10.1, Caddy Defender used `r.RemoteAddr` when evaluating whether a request should be blocked. `RemoteAddr` is the address of the immediate peer connected to Caddy. In deployments where Caddy is behind a trusted proxy, CDN, or load balancer, the immediate peer is usually the proxy, not the original client. Caddy resolves the original client address into its `client_ip` request variable after applying the configured `trusted_proxies` policy, but Defender did not use that value. As a result, clients from blocked IP ranges could bypass Defender when accessing Caddy through a trusted proxy whose own IP address was not blocked. This affects deployments that use Defender behind trusted proxies and expect it to enforce blocking based on the real client IP. The issue is fixed in version 0.10.1 by making Defender prefer Caddys resolved `client_ip` request variable when it is available. Defender falls back to `RemoteAddr` only when Caddy has not provided a resolved client IP. There is no complete workaround in affected Defender versions for deployments that rely on Caddy's trusted proxy client IP resolution. Until upgrading, affected users should enforce equivalent IP blocking at the trusted proxy, CDN, load balancer, firewall, or other edge layer before traffic reaches Caddy. Deployments where Caddy receives traffic directly from clients, without an intermediate trusted proxy, are not affected by this bypass.