mcp-proxy

Least-privilege permissions

• Run mcp-proxy with the minimum user account permissions needed—never as administrator or root—so if the proxy is compromised, attackers cannot access your entire system.
• Restrict the proxy's file system access to only the directories it absolutely needs; block read/write access to sensitive folders like credentials storage or database directories.
• Limit which MCP servers the proxy can connect to by whitelisting only approved endpoints; prevent it from reaching arbitrary internal systems.
• Use API keys or tokens with expiration dates and rotate them regularly; never store permanent credentials that the proxy can access.

Network isolation

• Enable TLS encryption (HTTPS) for all HTTP connections between your client and mcp-proxy in production; unencrypted HTTP exposes everything in transit.
• Run mcp-proxy on a private/internal network only—never expose it directly to the public internet; use a firewall to block external connections.
• Place mcp-proxy behind a network gateway or VPN so only authorized internal users or applications can reach it.
• Segment the proxy into its own network zone separate from sensitive systems (like databases or payment systems) so a breach cannot easily spread.

Monitoring

• Log all traffic passing through mcp-proxy (requests, responses, errors) and regularly review logs for unusual activity, failed connections, or repeated errors.
• Set alerts for suspicious patterns: sudden traffic spikes, unexpected error rates, or attempts to access unauthorized MCP servers.
• Track who is connecting to the proxy and from where; alert if unfamiliar IP addresses or user accounts appear.
• Conduct quarterly security audits of the proxy configuration, especially after updates, and test for common vulnerabilities.

Red flags to watch for

• No recent updates: If mcp-proxy hasn't been updated in many months or the maintainer is unresponsive to issues, plan to migrate to a maintained alternative.
• Cryptic or malformed error messages from the proxy that seem intentionally obfuscated—this may indicate tampering or a compromised version.
• Unexpected network connections from the proxy to unknown servers, or traffic patterns that don't match your normal usage.
• Credential leaks in logs or error messages: Search logs regularly for exposed API keys, passwords, or sensitive data that the proxy may have inadvertently logged.