CWE-321 Hard-coded Cryptographic Key

Description

Hard-coded Cryptographic Key

Reference: https://cwe.mitre.org/data/definitions/321.html

OWASP Category: A02:2021 – Cryptographic Failures

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Vulnerable Pattern

❌ Example 1: Vulnerable Pattern

// VULNERABLE: Hardcoded encryption key
private static final String SECRET_KEY = "MySecretKey12345";
private static final byte[] IV = "InitVector123456".getBytes();

SecretKeySpec keySpec = new SecretKeySpec(SECRET_KEY.getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, keySpec, new IvParameterSpec(IV));

Why it's vulnerable: This pattern is vulnerable to Hard-coded Cryptographic Key

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Deterministic Fix

✅ Secure Implementation: Secure Implementation

// SECURE: Generate keys securely and store externally
// Key generation (do once, store securely)
KeyGenerator keyGen = KeyGenerator.getInstance("AES");
keyGen.init(256, new SecureRandom());
SecretKey secretKey = keyGen.generateKey();

// Generate random IV for each encryption
byte[] iv = new byte[16];
new SecureRandom().nextBytes(iv);

// Load key from secure storage
@Value("${encryption.key}")
private String base64Key;

public SecretKey getKey() {
    byte[] keyBytes = Base64.getDecoder().decode(base64Key);
    return new SecretKeySpec(keyBytes, "AES");
}

// Use with random IV
Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, getKey(), new GCMParameterSpec(128, iv));

Why it's secure: Implements proper protection against Hard-coded Cryptographic Key

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Detection Pattern

Look for these patterns in your codebase:

# Find hardcoded key patterns
grep -rn "SecretKeySpec.*getBytes\|new.*Key.*\"" --include="*.java"

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Remediation Steps

1. Remove hardcoded keys from source code

2. Generate keys using KeyGenerator with SecureRandom

3. Store keys in secure key management system

4. Use random IV/nonce for each encryption operation

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Key Imports

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import java.security.SecureRandom;

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Verification

After remediation:

• Run SAST scanner to confirm vulnerability is resolved

• Review all instances of the vulnerable pattern

• Add unit tests that verify the secure implementation

• Check for similar patterns in related code

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Trigger Examples

Fix CWE-321 vulnerability
Resolve Hard-coded Cryptographic Key issue
Secure this Java code against hard-coded cryptographic key
SAST reports CWE-321

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Common Vulnerable Locations

Layer	Files	Patterns

| Controller | *Controller.java | User input handling |

| Service | *Service.java | Business logic |

| Repository | *Repository.java | Data access |

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References

• CWE-321: Hard-coded Crypto Key

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Source: Generated by Java CWE Security Skills Generator Last Updated: 2026-03-07