# 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: 中 3 言語をカバー
- Impact: ミディアム レビュー推奨
- Prevention: 文書化済み 5 件の修正例

**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

2 件の Shoulder 検出ルールに基づく Error Message Information Leak の予防策。

### 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

- アプリケーションデータの読み取り
- ファイルまたはディレクトリの読み取り

## Mitigations

- 例外は内部で処理し、ユーザーにエラーを表示しない
- 404 や 500 などの HTTP エラー用にデフォルトのエラーページを作成する
- サーバー側で詳細なエラーをログに記録し、ユーザーには汎用的なメッセージを表示する適切なエラー処理を実装する

## 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