8. Security Considerations
While MIME media types do not directly introduce security vulnerabilities, the use of certain types does pose security risks.
Potential Risks
1. Executable Content
Certain media types (such as application types) may contain executable code.
Risks:
- Malware distribution
- Code injection attacks
- Privilege escalation
Mitigation:
- Execute in sandboxes
- User confirmation
- Virus scanning
2. Content Type Spoofing
The declared media type may not match the actual content.
Risks:
- Bypass security filters
- Unexpected content parsing
- XSS attacks
Mitigation:
- Content sniffing validation
- Strict MIME type checking
- Content-Type Nosniff headers
3. Multipart Attacks
Complex multipart structures can be exploited.
Risks:
- Parser vulnerabilities
- Resource exhaustion
- Boundary confusion
Mitigation:
- Limit nesting depth
- Boundary validation
- Size limits
4. External-Body Risks
message/external-body may reference external resources.
Risks:
- Privacy leaks (tracking)
- SSRF attacks
- Malicious content loading
Mitigation:
- User confirmation
- URL whitelisting
- Disable automatic loading
Recommended Security Practices
- Type Validation: Verify Content-Type matches actual content
- Sandbox Execution: Process unknown types in isolated environments
- User Control: Let users control how dangerous types are handled
- Secure by Default: Use conservative handling for unknown types
- Regular Updates: Keep MIME processors up to date
Security Checklist:
- Validate Content-Type
- Restrict executable types
- Implement content scanning
- Set resource limits
- Log security events
- User education