CodeQL documentation
CodeQL resources

Use of a broken or risky cryptographic algorithm

ID: cpp/weak-cryptographic-algorithm
Kind: problem
Security severity: 7.5
Severity: error
Precision: high
Tags:
   - security
   - external/cwe/cwe-327
Query suites:
   - cpp-code-scanning.qls
   - cpp-security-extended.qls
   - cpp-security-and-quality.qls

Click to see the query in the CodeQL repository

Using broken or weak cryptographic algorithms may compromise security guarantees such as confidentiality, integrity, and authenticity.

Many cryptographic algorithms are known to be weak or flawed. The security guarantees of a system often rely on the underlying cryptography, so using a weak algorithm can have severe consequences. For example:

  • If a weak encryption algorithm is used, an attacker may be able to decrypt sensitive data.

  • If a weak hashing algorithm is used to protect data integrity, an attacker may be able to craft a malicious input that has the same hash as a benign one.

  • If a weak algorithm is used for digital signatures, an attacker may be able to forge signatures and impersonate legitimate users.

Recommendation

Ensure that you use a strong, modern cryptographic algorithm. Use at least AES-128 or RSA-2048.

Example

The following code shows an example of using the advapi windows API to decrypt some data. When creating a key, you must specify which algorithm to use. The first example uses DES which is an older algorithm that is now considered weak. The second example uses AES, which is a strong modern algorithm.

void advapi() {
  HCRYPTPROV hCryptProv;
  HCRYPTKEY hKey;
  HCRYPTHASH hHash;
  // other preparation goes here

  // BAD: use 3DES for key
  CryptDeriveKey(hCryptProv, CALG_3DES, hHash, 0, &hKey);

  // GOOD: use AES
  CryptDeriveKey(hCryptProv, CALG_AES_256, hHash, 0, &hKey);
}

References

  • © GitHub, Inc.
  • Terms
  • Privacy