Weak Hash Algorithm

ID

java.weak_hash_algorithm

Severity

critical

Resource

Cryptography

Language

Java

Tags

CWE:328, NIST.SP.800-53, OWASP:2021:A2, PCI-DSS:3.6.1, crypto

Description

Weak hash algorithm vulnerabilities arise when outdated or insufficiently secure hashing algorithms are used, making systems susceptible to threats such as hash collisions or preimage attacks.

This often involves the use of algorithms like MD5 or SHA-1.

Rationale

Hashing algorithms are essential for ensuring data integrity and verifying authenticity. However, algorithms like MD5 and SHA-1 are no longer considered secure due to vulnerabilities that allow attackers to find hash collisions or preimage matches efficiently. A collision occurs when two different inputs produce the same hash, which can lead to data tampering or fraudulent authentication.

For example, MD5 is susceptible to collision attacks, allowing attackers to substitute a malicious file for a legitimate one by ensuring both files generate the same hash. SHA-1, while more secure than MD5, is also vulnerable to collision attacks with current computational capabilities.

Consider the following example:

import java.security.MessageDigest;

public class WeakHashExample {
    public byte[] generateHash(String input) throws Exception {
        // Weak hash algorithm: MD5
        MessageDigest md = MessageDigest.getInstance("MD5");
        return md.digest(input.getBytes());
    }
}

In this example, MD5 is used to generate a hash. Due to its weaknesses, an attacker could potentially create different inputs that result in the same hash (a hash collision), compromising data integrity.

Remediation

To remediate weak hash algorithm vulnerabilities in software, adopt the following practices:

  1. Use Stronger Hash Algorithms: Replace weak algorithms like MD5 and SHA-1 with more secure options such as SHA-256 or SHA-3, which offer enhanced collision resistance and security.

  2. Cryptographic Libraries and Standards: Utilize well-supported libraries and standards that provide robust cryptographic hash functions. Ensure proper configuration and usage.

    In highly regulated environments, consider using cryptographic modules (which can encompass hardware devices, software libraries, firmware…​) compliant with standards like FIPS 140-3.

  3. Hashing in Secure Contexts: When hashing passwords, use additional strengthening techniques such as salting and key derivation functions like PBKDF2 or Bcrypt to enhance security.

  4. Periodic Reviews: Regularly evaluate your cryptographic implementations against the latest security research and recommendations, updating algorithms as needed.

Here is a secure implementation using SHA-256:

import java.security.MessageDigest;

public class SecureHashExample {
    public byte[] generateHash(String input) throws Exception {
        // Secure hash algorithm: SHA-256
        MessageDigest md = MessageDigest.getInstance("SHA-256");
        return md.digest(input.getBytes());
    }
}

By transitioning to SHA-256, this example mitigates risks associated with hash collisions and improves overall security. Continuing to evaluate and adopt stronger algorithms is crucial for maintaining data integrity and system reliability in the face of evolving cryptographic threats.

Configuration

The detector has the following configurable parameters:

  • allowedAlgorithms, that indicates the algorithms that are allowed to be used.

  • forbiddenAlgorithms, that indicates the algorithms that are considered weak and that should not be used.

References