Use of a weak cryptographic initialization vector

ID

java.weak_encryption_initialization_vector

Severity

critical

Resource

Cryptography

Language

Java

Tags

CWE:1204, NIST.SP.800-53, OWASP:2021:A2, PCI-DSS:6.5.3, crypto

Description

The improper use of initialization vectors (IVs) in encryption can weaken data security by enabling pattern detection and making the ciphertext vulnerable to attacks. It’s critical to ensure the IV is generated securely and used correctly to maintain encryption strength.

Rationale

Initialization vectors (IVs) are crucial in encryption schemes like CBC or GCM to ensure the same plaintext results in different ciphertexts. A weak or improperly used IV, such as a static or predictable one, can allow attackers to uncover patterns in the data, leading to potential data leaks or unauthorized access.

Consider the following Java code:

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.GCMParameterSpec;

public class EncryptionUtil {

  public static byte[] encrypt(byte[] data, SecretKey key) throws Exception {
    // Use a secure random IV for better security
    byte[] iv = new byte[16];

    GCMParameterSpec params = new GCMParameterSpec(128, iv);// FLAW

    Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
    cipher.init(Cipher.ENCRYPT_MODE, key, params);

    return cipher.doFinal(data);
  }
}

Remediation

To remediate issues with weak or improperly used IVs, ensure they are generated securely and uniquely for each encryption operation.

The remediation example for Java would look like this:

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.GCMParameterSpec;
import java.security.SecureRandom;

public class EncryptionUtil {

  public static byte[] encrypt(byte[] data, SecretKey key) throws Exception {
    // Use a secure random IV for better security
    byte[] iv = new byte[16];
    SecureRandom secureRandom = new SecureRandom();
    secureRandom.nextBytes(iv);

    GCMParameterSpec params = new GCMParameterSpec(128, iv);

    Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
    cipher.init(Cipher.ENCRYPT_MODE, key, params);

    return cipher.doFinal(data);
  }
}

References

  • CWE-1204 : Generation of Weak Initialization Vector (IV).