# Use of a Broken or Risky Cryptographic Algorithm (CWE-327)

The product uses a broken or risky cryptographic algorithm or protocol.

**Stack:** JavaScript

- Prevalence: 高 频繁被利用
- Impact: 高 3 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

Cryptographic algorithms are the backbone of modern information security. Using algorithms that have known weaknesses, such as MD5 or DES, can make it trivial for attackers to defeat the protection.

## Prevention

基于 2 条 Shoulder 检测规则的 Broken Cryptographic Algorithm 预防策略。

### JavaScript

Always specify allowed algorithms when verifying JWT tokens

Use SHA-256+ for hashing, AES-256-GCM for encryption, and bcrypt for passwords

## Warning Signs

- [HIGH] jwt.verify() without algorithm specification allows 'none' algorithm attack
- [HIGH] JWT verification without explicit algorithm specification, allowing "none" algorithm attacks that by
- [HIGH] use of weak or broken cryptographic algorithms for hashing passwords
or sensitive data

## Consequences

- 读取应用程序数据
- 绕过保护机制

## Mitigations

- 对称加密使用 AES-256
- 非对称加密使用 RSA-2048 以上或 ECDSA
- 哈希使用 SHA-256 或 SHA-3

## Detection

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

## Rules by Language

### Javascript (2 rules)

- **JWT Algorithm Confusion Attack** [HIGH]: Detects JWT verification without explicit algorithm specification, allowing "none" algorithm attacks that bypass authentication.
  - Remediation: Always specify allowed algorithms when verifying JWT tokens.
Example: jwt.verify(token, secret, { algorithms: ['RS256'] })
- **Use of Weak Cryptographic Algorithm** [HIGH]: Detects use of weak or broken cryptographic algorithms for hashing passwords
or sensitive data.

**Weak algorithms detected:**
- **MD5**: Cryptographically broken, vulnerable to collision attacks
- **SHA1**: Deprecated, vulnerable to collision attacks
- **DES/3DES**: Weak block cipher with small key size
- **RC4**: Stream cipher with known vulnerabilities

**Impact:**
- Password hashes can be cracked using rainbow tables or brute force
- Data encrypted with weak algorithms can be decrypted by at
  - Remediation: Use bcrypt/argon2 for passwords, SHA-256+ for hashing, and AES-256-GCM for encryption.

```javascript
const bcrypt = require('bcrypt');
const hash = await bcrypt.hash(password, 12);
```

Learn more: https://shoulder.dev/learn/javascript/cwe-327/weak-crypto-algorithm

### Typescript (2 rules)

- **JWT Algorithm Confusion Attack** [HIGH]: Detects JWT verification without explicit algorithm specification, allowing "none" algorithm attacks that bypass authentication.
  - Remediation: Always specify allowed algorithms when verifying JWT tokens.
Example: jwt.verify(token, secret, { algorithms: ['RS256'] })
- **Use of Weak Cryptographic Algorithm** [HIGH]: Detects use of weak or broken cryptographic algorithms for hashing passwords
or sensitive data.

**Weak algorithms detected:**
- **MD5**: Cryptographically broken, vulnerable to collision attacks
- **SHA1**: Deprecated, vulnerable to collision attacks
- **DES/3DES**: Weak block cipher with small key size
- **RC4**: Stream cipher with known vulnerabilities

**Impact:**
- Password hashes can be cracked using rainbow tables or brute force
- Data encrypted with weak algorithms can be decrypted by at
  - Remediation: Use bcrypt/argon2 for passwords, SHA-256+ for hashing, and AES-256-GCM for encryption.

```javascript
const bcrypt = require('bcrypt');
const hash = await bcrypt.hash(password, 12);
```

Learn more: https://shoulder.dev/learn/javascript/cwe-327/weak-crypto-algorithm