Know MCP risks before you deploy!

The Model Context Protocol (MCP) is emerging as a powerful standard for enabling AI agents to interact with tools and data. However, like any evolving technology, MCP introduces new security challenges that organizations must address before deploying it in production environments.

Major MCP Vulnerabilities

MCP’s flexibility comes with risks. Here are the most critical vulnerabilities:

1. Prompt Injection

Attackers embed hidden instructions in user input, manipulating the model to trigger unauthorized MCP actions and bypass safety rules.

 

2. Tool Poisoning

Malicious MCP servers provide misleading tool descriptions or parameters, tricking agents into leaking sensitive data or executing harmful commands.

 

3. Remote Code Execution

Untrusted servers can inject OS-level commands through compromised endpoints, enabling full control over the host environment.

 

4. Unauthenticated Access

Rogue MCP servers bypass authentication and directly call sensitive tools, extracting internal data without user consent.

 

5. Confused Deputy (OAuth Proxy)

A malicious server misuses OAuth tokens issued for a trusted agent, performing unauthorized actions under a legitimate identity.

 

6. MCP Configuration Poisoning

Attackers silently modify approved configuration files so agents execute malicious commands as if they were part of the original setup.

 

7. Token or Credential Theft

Plaintext MCP config files expose API keys, cloud credentials, and access tokens, making them easy targets for malware or filesystem attacks.

 

8. Path Traversal

Older MCP filesystem implementations allow navigation outside the intended directory, exposing sensitive project or system files.

 

9. Token Passthrough

Some servers blindly accept forwarded tokens, allowing compromised agents to impersonate other services without validation.

 

10. Session Hijacking

Session IDs appearing in URLs can be captured from logs or redirects and reused to access active sessions.

Current Known Limitations

While MCP is promising, it has structural limitations that organizations must plan for:

1. Lack of Native Tool Authenticity Verification

There is no built-in mechanism to verify if a tool or server is genuine. Trust relies on external validation, increasing exposure to tool poisoning attacks.

 

2. Weak Context Isolation

Multi-session environments risk cross-contamination, where sensitive data from one session leaks into another.

 

3. Limited Built-In Encryption Enforcement

MCP depends on HTTPS/TLS for secure communication but does not enforce encryption across all channels by default.

 

4. Monitoring & Auditing Gaps

MCP lacks native logging and auditing capabilities. Organizations must integrate with external SIEM tools like Microsoft Sentinel for visibility.

 

5. Dynamic Registration Risks

Current implementations allow dynamic client registration without granular controls, enabling rogue client onboarding.

 

6. Scalability Constraints

Large-scale deployments require manual tuning for performance and security. There is no standardized approach for load balancing or high availability.

 

7. Configuration Management Challenges

Credentials often stored in plaintext within MCP config files. Lack of automated secret rotation or secure vault integration makes them vulnerable.

 

8. Limited Standardization Across Vendors

MCP is still evolving, and interoperability between different implementations is inconsistent, creating integration complexity.

Mitigation Best Practices

To reduce risk and strengthen MCP deployments:

• Enforce OAuth 2.1 with PKCE and strong RBAC.
• Use HTTPS/TLS for all MCP communications.
• Deploy MCP servers in isolated networks with private endpoints.
• Validate tools before integration; avoid untrusted sources.
• Integrate with Microsoft Defender for Cloud and Sentinel for monitoring.
• Encrypt and rotate credentials; never store in plaintext.
• Implement policy-as-code for configuration governance.

MCP opens new possibilities for AI-driven automation, but without robust security, it can become an attack vector. Organizations must start with a secure baseline, continuously monitor, and adopt best practices to operationalize MCP safely.