CWE-780: Use of RSA Algorithm without OAEP

Description

The product uses the RSA algorithm but does not incorporate Optimal Asymmetric Encryption Padding (OAEP), which might weaken the encryption.

Padding schemes are often used with cryptographic algorithms to make the plaintext less predictable and complicate attack efforts. The OAEP scheme is often used with RSA to nullify the impact of predictable common text.

Potential Impact

Access Control

Bypass Protection Mechanism

Demonstrative Examples

The example below attempts to build an RSA cipher.

Bad

public Cipher getRSACipher() {Cipher rsa = null;try {rsa = javax.crypto.Cipher.getInstance("RSA/NONE/NoPadding");}catch (java.security.NoSuchAlgorithmException e) {log("this should never happen", e);}catch (javax.crypto.NoSuchPaddingException e) {log("this should never happen", e);}return rsa;}

While the previous code successfully creates an RSA cipher, the cipher does not use padding. The following code creates an RSA cipher using OAEP.

Good

public Cipher getRSACipher() {Cipher rsa = null;try {rsa = javax.crypto.Cipher.getInstance("RSA/ECB/OAEPWithMD5AndMGF1Padding");}catch (java.security.NoSuchAlgorithmException e) {log("this should never happen", e);}catch (javax.crypto.NoSuchPaddingException e) {log("this should never happen", e);}return rsa;}

Detection Methods

Automated Static Analysis High — Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then sea

Frequently Asked Questions

What is CWE-780?

CWE-780 (Use of RSA Algorithm without OAEP) is a software weakness identified by MITRE's Common Weakness Enumeration. It is classified as a Variant-level weakness. The product uses the RSA algorithm but does not incorporate Optimal Asymmetric Encryption Padding (OAEP), which might weaken the encryption.

How can CWE-780 be exploited?

Attackers can exploit CWE-780 (Use of RSA Algorithm without OAEP) to bypass protection mechanism. This weakness is typically introduced during the Implementation phase of software development.

How do I prevent CWE-780?

Follow secure coding practices, conduct code reviews, and use automated security testing tools (SAST/DAST) to detect this weakness early in the development lifecycle.

What is the severity of CWE-780?

CWE-780 is classified as a Variant-level weakness (Low-Medium abstraction). Its actual severity depends on the specific context and how the weakness manifests in your application.