Intermediate LevelAI, LLMs, Embeddings & MCP
How do you secure MCP Servers against dangerous tool calls and local filesystem path traversal?
❓ Interview Prompt: Explain Model Context Protocol security vulnerabilities: path traversal, command injection, and human-in-the-loop permission gates.
Exposing system tools and file access to LLMs via Model Context Protocol (MCP) creates major security attack vectors if un-sanitized.
Essential MCP Security Controls:
1
Path Traversal Sanitization: Validate that resource URIs and file path arguments stay restricted within allowed root directories (preventing
../../etc/passwd exploits).2
Command Injection Prevention: Never pass un-sanitized LLM parameters directly to shell commands (
exec). Use parameterized APIs.3
Human-In-The-Loop (HITL) Gates: Prompt end-user UI approval before executing high-risk tools (e.g.
delete_database, send_payment).Code Implementation Example
typescript
import path from 'path';
function sanitizeMcpFilePath(requestedPath: string, allowedDir: string): string {
// Resolve absolute path
const safePath = path.normalize(path.join(allowedDir, requestedPath));
// Verify resolved path stays strictly within allowed base directory
if (!safePath.startsWith(path.resolve(allowedDir))) {
throw new Error('Security Error: Path traversal outside sandbox boundary!');
}
return safePath;
}💡Path traversal validation for MCP file resource access.
🎯 Interview Key Takeaway
Secure MCP servers using strict path canonicalization, command parameterization, and Human-In-The-Loop execution gates.
#MCP Security#Path Traversal#Sanitization#HITL#Intermediate
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