# Insertion of Sensitive Information into Log File (CWE-532)

Information written to log files can be of a sensitive nature and give valuable guidance to an attacker or expose sensitive user information.

- Prevalence: 中 覆盖 3 种语言
- Impact: 高 1 条严重级别为高的规则
- Prevention: 已记录 3 个修复示例

**OWASP:** Security Logging and Monitoring Failures (A09:2021-Security Logging and Monitoring Failures) - #9

## Description

When sensitive information like passwords, tokens, or personal data is logged, it becomes accessible to anyone with access to the logs. Log files are often stored with less security than the data they contain.

## Prevention

基于 3 条 Shoulder 检测规则的 Information Exposure Through Logs 预防策略。

### Go

Never log passwords, tokens, or PII; log presence/absence instead

### JavaScript

Exclude sensitive fields from logged data using destructuring or redaction

### Python

Redact sensitive fields before logging; log actions and identifiers, not credentials

## Warning Signs

- [HIGH] logging of sensitive data like passwords, API keys, tokens, credit
cards, or authentication credenti
- [MEDIUM] when user-provided sensitive data (passwords, tokens, API keys, secrets, etc

## Consequences

- 读取应用程序数据
- 获取权限

## Mitigations

- 切勿在日志中记录密码或令牌等敏感信息
- 实施日志数据的分类和过滤
- 在记录之前对敏感数据进行掩码或脱敏

## Detection

- Total rules: 3
- Languages: go, javascript, typescript, python

## Rules by Language

### Go (1 rules)

- **Logging Sensitive Data** [MEDIUM]: Passwords, tokens, or PII logged via log.Printf or similar functions.
  - Remediation: Never log sensitive values. Log presence/absence instead of actual values.

```go
// Log only that API key is configured, not the value
if apiKey != "" {
    log.Println("API key configured")
}
```

Learn more: https://shoulder.dev/learn/go/cwe-532/sensitive-data-logging

### Javascript (1 rules)

- **Sensitive Data Exposure in Logs** [MEDIUM]: Detects when user-provided sensitive data (passwords, tokens, API keys, secrets, etc.)
flows directly into logging functions without proper redaction or masking.

This rule uses taint flow analysis to detect ACTUAL sensitive data being logged,
not just variables with sensitive names. Only triggers when:
1. Data originates from user input (req.body, req.headers, etc.)
2. Contains sensitive field names (password, token, secret, etc.)
3. Flows into logging functions without sanitization

Sensitive 
  - Remediation: Exclude sensitive fields from logged data:

```javascript
const { password, ...safeBody } = req.body;
console.log('Request body:', safeBody);

function redactToken(token) {
  return token ? token.substring(0, 4) + '***' : '';
}
logger.info('Token:', redactToken(authToken));
```

Learn more: https://shoulder.dev/learn/javascript/cwe-532/sensitive-data-logging

### Typescript (1 rules)

- **Sensitive Data Exposure in Logs** [MEDIUM]: Detects when user-provided sensitive data (passwords, tokens, API keys, secrets, etc.)
flows directly into logging functions without proper redaction or masking.

This rule uses taint flow analysis to detect ACTUAL sensitive data being logged,
not just variables with sensitive names. Only triggers when:
1. Data originates from user input (req.body, req.headers, etc.)
2. Contains sensitive field names (password, token, secret, etc.)
3. Flows into logging functions without sanitization

Sensitive 
  - Remediation: Exclude sensitive fields from logged data:

```javascript
const { password, ...safeBody } = req.body;
console.log('Request body:', safeBody);

function redactToken(token) {
  return token ? token.substring(0, 4) + '***' : '';
}
logger.info('Token:', redactToken(authToken));
```

Learn more: https://shoulder.dev/learn/javascript/cwe-532/sensitive-data-logging

### Python (1 rules)

- **Sensitive Data in Logging** [HIGH]: Detects logging of sensitive data like passwords, API keys, tokens, credit
cards, or authentication credentials. Logged sensitive data can be exposed
through log files, monitoring systems, or error tracking services.
  - Remediation: Redact sensitive fields before logging; log actions and usernames, not credentials.

```python
import logging

logger = logging.getLogger(__name__)

SENSITIVE = {'password', 'token', 'api_key', 'secret'}

def sanitize(data):
    return {k: '***' if k in SENSITIVE else v for k, v in data.items()}

def login(username, password):
    logger.info(f"Login attempt for: {username}")  # Log username, not password
    authenticate(username, password)
```

Learn more: https://shoulder.dev/learn/python/cwe-532/sensitive-data-logging