# Generation of Error Message Containing Sensitive Information (CWE-209)

The product generates an error message that includes sensitive information about its environment, users, or associated data.

**Stack:** Python

- Prevalence: Medium 3 languages covered
- Impact: Medium Review recommended
- Prevention: Documented 5 fix examples

**OWASP:** Insecure Design (A04:2021-Insecure Design) - #4

## Description

The sensitive information may be valuable information on its own, or it may be useful for launching other, more serious attacks. The error message may be created in different ways, and the information that is included can range widely.

## Prevention

Prevention strategies for Error Message Information Leak based on 2 Shoulder detection rules.

### Python

Log full exception details internally but return generic error messages to users

Return generic responses; log internal paths server-side only

## Warning Signs

- [MEDIUM] error messages that expose sensitive implementation details like
stack traces, database errors, file
- [MEDIUM] responses that include internal file paths, IP addresses, or system
information

## Consequences

- Read Application Data
- Read Files or Directories

## Mitigations

- Handle exceptions internally and do not display errors to the user
- Create default error pages for HTTP errors such as 404 and 500
- Implement proper error handling that logs detailed errors server-side but shows generic messages to users

## Detection

- Total rules: 5
- Languages: go, javascript, typescript, python

## Rules by Language

### Python (2 rules)

- **Error Message Information Disclosure** [MEDIUM]: Detects error messages that expose sensitive implementation details like
stack traces, database errors, file paths, or internal system information.
This information can help attackers understand the system architecture.
  - Remediation: Log full exception details internally but return generic error messages to users.

```python
import logging
from flask import jsonify

logger = logging.getLogger(__name__)

@app.route('/api/data')
def get_data():
    try:
        return jsonify(process_data())
    except Exception as e:
        logger.error(f"Processing failed: {e}", exc_info=True)
        return jsonify({'error': 'Internal server error'}), 500
```

Learn more: https://shoulder.dev/learn/python/cwe-209/error-message-exposure
- **Internal Path and IP Address Disclosure** [MEDIUM]: Detects responses that include internal file paths, IP addresses, or system
information. This information helps attackers understand the system architecture,
file structure, and internal network topology.
  - Remediation: Return generic error messages; log internal details without exposing them in responses.

```python
import logging
from flask import jsonify

logger = logging.getLogger(__name__)

@app.route('/info')
def get_info():
    logger.info(f"Request to {__file__}")  # Log internally
    return jsonify({'status': 'ok', 'version': '1.0'})  # Generic response
```

Learn more: https://shoulder.dev/learn/python/cwe-209/internal-path-disclosure