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A good practice is to always use a salt in addition to the password being hashed. A salt is a unique randomly generated piece of data that is stored and used to generate the hash value along with the password. along with the hash value. Each Each password should have its own salt associated with it. If a single salt were used for more than one password an attacker could determine when a user has a commonly used password. Password specific salts are usually stored along with their corresponding hash values. System specific In addition to password-unique salts, system-unique salts that are stored separately from the hash values may also be used to increase the difficulty of deriving passwords if a malicious actor obtains a copy of the hash values and salts.
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| Code Block | ||
|---|---|---|
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public final class Password {
private void setPassword(byte[] pass) throws Exception {
// Arbitrary encryption scheme
byte[] encrypted = encrypt(pass);
clearArray(pass);
// Encrypted password to password.bin
saveBytes(encrypted,"password.bin");
clearArray(encrypted);
}
boolean checkPassword(byte[] pass) throws Exception {
// Load the encrypted password
byte[] encrypted = loadBytes("password.bin");
byte[] decrypted = decrypt(encrypted);
clearArray(encrypted);
boolean arraysEqual = Arrays.equal(decrypted, pass);
clearArray(decrypted);
clearArray(pass);
return arraysEqual;
}
private void clearArray(byte[] a) {
for (int i = 0; i < a.length; i++) {
a[i] = 0;
}
}
private byte[] encrypt(byte[] clearValue) {
// ... symmetric encryption of clearValue bytes, returning the encrypted value
}
private byte[] decrypt(byte[] encryptedValue) {
// ... symmetric decryption of encryptedValue bytes, returning clear value
}
private void saveBytes(byte[] bytes, String filename) throws IOException {
// ... write bytes to the file
}
private byte[] loadBytes(String filename) throws IOException {
// ... read bytes to the file
}
}
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| Code Block | ||
|---|---|---|
| ||
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public final class Password {
private SecureRandom random = new SecureRandom();
private void setPassword(String pass) throws Exception {
byte[] salt = new byte[12];
random.nextBytes(salt);
MessageDigest msgDigest = MessageDigest.getInstance("SHA-256");
// Encode the string and salt
byte[] hashVal = msgDigest.digest((pass+salt).getBytes());
saveBytes(salt, "salt.bin");
// Save the hash value to password.bin
saveBytes(hashVal,"password.bin");
}
boolean checkPassword(String pass) throws Exception {
byte[] salt = loadBytes("salt.bin");
MessageDigest msgDigest = MessageDigest.getInstance("SHA-256");
// Encode the string and salt
byte[] hashVal1 = msgDigest.digest((pass+salt).getBytes());
// Load the hash value stored in password.bin
byte[] hashVal2 = loadBytes("password.bin");
return Arrays.equals(hashVal1, hashVal2);
}
private void saveBytes(byte[] bytes, String filename) throws IOException {
// ... write bytes to the file
}
private byte[] loadBytes(String filename) throws IOException {
// ... read bytes to the file
}
}
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Applications such as password managers may need to retrieve the original password to enter it into a third-party application. This is permitted even though it violates this guideline. The password manager is accessed by a single user and always has the user's permission to store his or her passwords and to display those passwords on command. Consequently, the limiting factor to safety and security is the user's competence rather than the program's operation.
Automated Detection
| Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Parasoft Jtest |
| CERT.MSC62.PCCF CERT.MSC62.PWDPROP CERT.MSC62.PWDXML CERT.MSC62.WCPWD CERT.MSC62.WPWD CERT.MSC62.PLAIN CERT.MSC62.PTPT CERT.MSC62.UTAX | Avoid storing usernames and passwords in plain text in Castor 'jdo-conf.xml' files Ensure that passwords are not stored as plaintext and are sufficiently long Ensure that passwords are not stored as plaintext and are sufficiently long Avoid unencrypted passwords in WebSphere 'ibm-webservicesclient-ext.xmi' files Avoid unencrypted passwords in WebSphere 'ibm-webservices-ext.xmi' files Password information should not be included in properties file in plaintext Avoid using plain text passwords in Axis 'wsdd' files Avoid using plain text passwords in Axis2 configuration files |
Bibliography
| [API 2013] | |
| [Hirondelle 2013] | Passwords Never Clear in Text |
| [OWASP 2012] | "Why Add Salt?" |
| [Paar 2010] | Chapter 11, "Hash Functions" |
| OWASP ASVS | |
| [NIST 2017] | NIST 800-63 |
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