RSA encryption using insecure PKCS#1 v1.5 padding

ID

vbnet.cryptography.inadequate_padding

Severity

high

Remediation Complexity

medium

Remediation Risk

medium

Remediation Effort

medium

Resource

Cryptography

Language

VB.NET

Description

RSA encryption is using the outdated PKCS#1 v1.5 padding (fOAEP=False or RSAEncryptionPadding.Pkcs1). PKCS#1 v1.5 is vulnerable to padding-oracle (Bleichenbacher) attacks. Use OAEP padding instead, e.g. RSAEncryptionPadding.OaepSHA256 or Encrypt(data, True).

Rationale

RSA encryption is using the outdated PKCS#1 v1.5 padding (fOAEP=False or RSAEncryptionPadding.Pkcs1). PKCS#1 v1.5 is vulnerable to padding-oracle (Bleichenbacher) attacks. Use OAEP padding instead, e.g. RSAEncryptionPadding.OaepSHA256 or Encrypt(data, True).

The following code illustrates a vulnerable pattern detected by this rule:

Public Function EncryptLegacy(rsa As RSACryptoServiceProvider, data As Byte()) As Byte()
    ' VULNERABLE: RSA encryption using insecure PKCS#1 v1.5 padding
    Return rsa.Encrypt(data, False)
End Function

Remediation

Follow secure coding practices and review the references below for detailed remediation guidance.

Configuration

This detector does not need any configuration.

References