# Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) (CWE-338)

The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.

**Stack:** Go

- Prevalence: 高 频繁被利用
- Impact: 高 2 条严重级别为高的规则
- Prevention: 已记录 4 个修复示例

**OWASP:** Cryptographic Failures (A02:2021-Cryptographic Failures) - #2

## Description

When a non-cryptographic PRNG is used in a security context (such as generating session tokens or cryptographic keys), an attacker may be able to predict its output and compromise the security mechanism.

## Prevention

基于 1 条 Shoulder 检测规则的 Weak PRNG 预防策略。

### Go

Use crypto/rand instead of math/rand for security-sensitive values

## Warning Signs

- [HIGH] math/rand used for security-sensitive random values

## Consequences

- 绕过保护机制
- 获取权限

## Mitigations

- 使用密码学安全的随机数生成器 (CSPRNG)
- 在 JavaScript 中使用 crypto.getRandomValues() 或 crypto.randomUUID()
- 在 Python 中使用 secrets 模块,而不是 random

## Detection

- Total rules: 4
- Languages: go, javascript, typescript, python

## Rules by Language

### Go (1 rules)

- **Weak Random Number Generation for Security** [HIGH]: Uses math/rand for security tokens, keys, or session IDs instead of crypto/rand.
  - Remediation: Use crypto/rand for all security-sensitive random values.

```go
import "crypto/rand"

token := make([]byte, 32)
if _, err := rand.Read(token); err != nil {
    return err
}
```

Learn more: https://shoulder.dev/learn/go/cwe-338/weak-random