Chapter 6.3: Securing MCP (Model Context Protocol) - The Essential Developer Checklist

Описание: Welcome to the final part of our three-part series on Model Context Protocol (MCP) Security!

This video serves as a capstone summary and essential checklist for developers building MCP servers or clients. While MCP simplifies M×N connectivity problems into M+N, driving explosive adoption (like within OpenAI’s Agent Builder in ChatGPT), many critical security aspects are left entirely to the developer.

Why MCP Security is Critical
MCP components include the host system, the MCP client (e.g., Cloud Desktop, MCP Inspector), and MCP servers, which expose tools, resources, and system prompts.
Crucially, all MCP servers must be treated as untrusted entities. Servers can send malicious tool descriptions, attempt unsafe LLM sampling, or initiate risky elicitation requests for structured data.

We highlight real-world, widespread vulnerabilities:
• Command Injection: A shocking 43% of MCP servers have been found vulnerable to command injection. This issue, often stemming from the unsafe use of shell=True in child process execution, led to a real-world Remote Code Execution (RCE) vulnerability in the Figma MCP server (which received a CVE).
• Path Traversal / Directory Traversal: Poor input validation allows attackers to use ../ sequences or symbolic links to access unauthorized sensitive files, such as SSH private keys, environment variables, or Unix password files.
• Server-Initiated Prompt Injection: Unlike typical prompt injection, the MCP server can inject instructions (via tool descriptions or system prompts) directly into the client’s LLM, potentially causing unintended or malicious behaviour.

Core Security Risks & Principles
We dive into additional attack vectors and foundational security principles:
• Supply Chain Attacks: Malicious packages are a major concern; a package called “MCP remote” was downloaded nearly 500,000 times before being removed as malware. Rugpull attacks and dependency confusion also pose significant risks.
• Confused Deputy Problem: Improper session management or predictable session IDs can allow an attacker to confuse the server (acting as a deputy between clients and services like Slack) into mixing user requests, leading to unauthorized data leakage.
• Network Risks: Binding MCP servers to 0.0.0.0 exposes them to the entire local network; they should be strictly bound to 127.0.0.1 (localhost). Even testing tools are vulnerable—MCP Inspector itself had a critical CVSS 9.4 RCE vulnerability.
• Zero Trust and Least Privilege are foundational requirements for all MCP interactions.

The Secure Coding Checklist for MCP Developers:
1. Transport & Network: Use HTTPS and never bind to 0.0.0.0.
2. Input Validation: Rigorously validate all input and output to prevent command injection and directory traversal.
3. Shell Execution: Avoid shell=True in command execution; prefer safer alternatives.
4. Resource Restrictions (Roots): Clients must enforce strict folder constraints on resources accessed by the server.
5. Path Handling: Canonicalize and validate paths to resolve symbolic links before access.
6. Authentication (OAuth 2.1): Implement proper OAuth using the framework requirements: Proof Key for Code Exchange (PKCE), Resource Indicators (binding tokens to specific servers), and the Protected Resource Mandate.
7. Environment: Run all MCP components in sandboxed/containerized environments.


Action Plan for Operators and Users
For Developers & Operators:
• Audit existing MCP servers using secure coding tools.
• Automate security testing within your CI/CD pipelines (DevSecOps).
• Catalog all MCP servers, permissions, tools, and resources in your environment.
• Establish governance processes for vetting new MCP tools before deployment.

For End Users:
• Review installed MCP tools and immediately remove untrusted ones.
• Revoke unnecessary permissions.
• Enable confirmation prompts before any tool execution.

About the Instructor:
KK Mookhey is a cybersecurity expert with over 25 years of experience. This series provides practical, hands-on training in building and securing AI applications for cybersecurity professionals.
Connect with KK   / kkmookhey  

Reference blog for checklist: https://www.networkintelligence.ai/bl...

Code Samples: https://docs.google.com/document/d/1N...

Timestamps:
00:01 → Introduction and Context
00:40 → Overview of MCP Protocol and Its Adoption
02:05 → MCP Architecture Components and Trust Model
03:25 → Key Vulnerabilities in MCP Servers
05:44 → Prompt Injection Risks
06:51 → Authentication, Confused Deputy, and Supply Chain Attacks
10:34 → Security Best Practices and OAuth 2.1 Framework
11:49 → Secure Coding Checklist for MCP Developers

#MCP #Cybersecurity#cybersecurity #AISecurity #CommandInjection #ZeroTrust