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  1. Rules Repository
  2. RSPEC-3275

IV's should be random and unique

    Details

    • Type: Vulnerability Detection
    • Status: Closed
    • Resolution: Duplicate
    • Labels:
    • Message:
      Hide
      * Remove this hard-coded IV.
      * Use "SecureRandom" instead of "Random" to create this IV.
      * Generate a new IV for each encryption cycle.
      Show
      * Remove this hard-coded IV. * Use "SecureRandom" instead of "Random" to create this IV. * Generate a new IV for each encryption cycle.
    • Default Severity:
      Critical
    • Impact:
      High
    • Likelihood:
      Low
    • Default Quality Profiles:
      Sonar way
    • Targeted languages:
      C#, C++, Java, Objective-C, PHP, Python, Swift, VB.Net
    • Remediation Function:
      Constant/Issue
    • Constant Cost:
      15min
    • Implementation details:
    • CWE:
      CWE-329

      Description

      When CBC (Cypher Block Chaining) is used for encryption, the IV (Initialization Vector) must be random an unpredictable. Otherwise it exposes the encrypted value to crypto-analysis attacks like "Chosen-Plaintext Attacks".

      An IV should be used in one and only one encryption cycle because its purpose is to ensure that a different cyphertext value results each time a given plain text value is encrypted.

      Noncompliant Code Example

      public String cbcEncrypt(String strKey, String plainText) {

  String strIV = "7cVgr5cbdCZVw5WY";
  IvParameterSpec ivSpec = new IvParameterSpec(strIV.getBytes("UTF-8"));
  SecretKeySpec skeySpec = new SecretKeySpec(strKey.getBytes("UTF-8"), "AES");

  /* Ciphering */
  Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
  cipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivSpec);  // Noncompliant
  byte[] encryptedBytes = cipher.doFinal(plaintText.getBytes("UTF-8"));
  return DatatypeConverter.printBase64Binary(ivBytes) + ";" + DatatypeConverter.printBase64Binary(encryptedBytes);
}

      Compliant Solution

      private SecureRandom random = new SecureRandom();

public void cbcEncrypt(String strKey, String plainText) {

  byte ivBytes[] = new byte[16];
  random.nextBytes(ivBytes);
  IvParameterSpec ivSpec = new IvParameterSpec(ivBytes);
  SecretKeySpec skeySpec = new SecretKeySpec(strKey.getBytes("UTF-8"), "AES");

  /* Ciphering */
  Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
  cipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivSpec); 
  byte[] encryptedBytes = cipher.doFinal(plaintText.getBytes("UTF-8"));
  return DatatypeConverter.printBase64Binary(ivBytes) + ";" + DatatypeConverter.printBase64Binary(encryptedBytes);
}

      See

      • MITRE, CWE-329 - Not Using a Random IV with CBC Mode
      • OWASP Top 10 2017 Category A6 - Security Misconfiguration

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          is duplicated by

          Vulnerability Detection - RSPEC-3329 Cypher Block Chaining IV's should be random and unique

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              • Assignee:
                Unassigned
                Reporter:
                ann.campbell.2 Ann Campbell
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                Dates

                • Created:
                  Updated:
                  Resolved: