Details
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Type:
Vulnerability Detection
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Status: Closed
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Resolution: Duplicate
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Message:
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Default Severity:Critical
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Impact:High
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Likelihood:Low
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Default Quality Profiles:Sonar way
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Targeted languages:C#, C++, Java, Objective-C, PHP, Python, Swift, VB.Net
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Remediation Function:Constant/Issue
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Constant Cost:15min
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Implementation details:
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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
Attachments
Issue Links
- is duplicated by
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- Active
