How do I find hidden proxy?

Could you please elaborate on the process of identifying hidden proxies? Are there specific tools or techniques that you recommend using? Are there any common indicators or signs that can help pinpoint the presence of a hidden proxy? Additionally, could you discuss the potential risks associated with hidden proxies and why it's important to detect and manage them? Lastly, are there any best practices for mitigating the risks posed by hidden proxies in a secure and effective manner?