Cryptographic hash algorithms such as MD2, MD4, MD5, MD6, HAVAL-128,
HMAC-MD5, DSA (which uses SHA-1), RIPEMD, RIPEMD-128, RIPEMD-160,
HMACRIPEMD160 and SHA-1 are no longer considered secure, because it is possible to have collisions (little
computational effort is enough to find two or more different inputs that produce the same hash).
Ask Yourself Whether
The hashed value is used in a security context like:
- User-password storage.
- Security token generation (used to confirm e-mail when registering on a website, reset password, etc …).
- To compute some message integrity.
There is a risk if you answered yes to any of those questions.
Recommended Secure Coding Practices
Safer alternatives, such as SHA-256, SHA-512, SHA-3 are recommended, and for password hashing, it’s even
better to use algorithms that do not compute too "quickly", like bcrypt, scrypt, argon2 or pbkdf2
because it slows down brute force attacks.
Sensitive Code Example
var hashProvider1 = new MD5CryptoServiceProvider(); // Sensitive
var hashProvider2 = (HashAlgorithm)CryptoConfig.CreateFromName("MD5"); // Sensitive
var hashProvider3 = new SHA1Managed(); // Sensitive
var hashProvider4 = HashAlgorithm.Create("SHA1"); // Sensitive
Compliant Solution
var hashProvider1 = new SHA512Managed(); // Compliant
var hashProvider2 = (HashAlgorithm)CryptoConfig.CreateFromName("SHA512Managed"); // Compliant
var hashProvider3 = HashAlgorithm.Create("SHA512Managed"); // Compliant
See
