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Insecure encryption algorithm - SSLContext

Need​

Implementation of secure encryption algorithms for SSLContext

Context​

  • Usage of Dart for building cross-platform mobile, web, and desktop applications
  • Usage of dart:io for handling input/output operations in Dart programming

Description​

Non compliant code​

import 'dart:io';

void main() {
  HttpServer.bindSecure('127.0.0.1', 4040, 
    SecurityContext()
      ..useCertificateChain('example_cert.pem')
      ..usePrivateKey('example_key.pem'),
    supportedProtocols: ['sslv3'],
  )
    .then((server) {
      server.listen((HttpRequest request) {
        request.response
          ..write('Hello, world!')
          ..close();
      });
    });
}

The above Dart code is a simple HTTPS server using the HttpServer.bindSecure method from the dart:io library. The SecurityContext object is used to provide the server's certificate and private key.

The vulnerability lies in the supportedProtocols parameter, which is set to only support the SSLv3 protocol. SSLv3 is an outdated and insecure protocol that is susceptible to a number of attacks, including the POODLE (Padding Oracle On Downgraded Legacy Encryption) attack.

In the POODLE attack, an attacker can exploit the way SSLv3 handles padding to decrypt sensitive information from the encrypted communication. This can potentially expose sensitive user data to the attacker.

In addition to the POODLE attack, SSLv3 does not support modern cryptographic algorithms, making it less secure than its successors TLS 1.2 and TLS 1.3. Therefore, the use of SSLv3 in this code is an insecure encryption algorithm vulnerability.

Steps​

  • Identify the insecure protocol being used. In this case, it's 'sslv3'.
  • Replace the insecure protocol with a secure one. The most secure protocol currently is 'TLSv1.3'.
  • Ensure that the server supports the secure protocol. This might require updating the server or its libraries.
  • Test the application to ensure that the secure protocol is being used and that the application is functioning as expected.

Compliant code​

import 'dart:io';

void main() {
  HttpServer.bindSecure('127.0.0.1', 4040, 
    SecurityContext()
      ..useCertificateChain('example_cert.pem')
      ..usePrivateKey('example_key.pem'),
    supportedProtocols: ['TLSv1.3'],
  )
    .then((server) {
      server.listen((HttpRequest request) {
        request.response
          ..write('Hello, world!')
          ..close();
      });
    });
}

The original code was using the 'sslv3' protocol, which is considered insecure due to numerous vulnerabilities that have been discovered over the years. The updated code now uses the 'TLSv1.3' protocol, which is currently the most secure protocol available.

The 'TLSv1.3' protocol provides numerous security benefits over 'sslv3', including improved encryption, more secure handshake processes, and the removal of insecure features and cipher suites found in previous versions.

The HttpServer.bindSecure method is used to bind the server to an IP address and port, and to specify the security context and supported protocols. The SecurityContext object is used to specify the certificate chain and private key for secure communication.

The supportedProtocols parameter is used to specify the protocols that the server supports. In this case, it has been updated to only support 'TLSv1.3'.

After making these changes, it's important to test the application to ensure that the secure protocol is being used and that the application is functioning as expected. This might require updating the server or its libraries to support 'TLSv1.3'.

References​

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