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Use of an insecure channel - SMTP

Description​

The configuration of the SMTP service is set to not use SSL, so confidential information traveling by this means that can be viewed without any type of encryption.

Impact​

Obtain and modify confidential information sent by SMTP.

Recommendation​

Deploy the application over an encrypted communication channel, use SSL secure protocols.

Threat​

Unauthorized internal attacker.

Expected Remediation Time​

⌚ 60 minutes.

Score​

Default score using CVSS 3.1. It may change depending on the context of the vulnerability.

Base​

  • Attack vector: A
  • Attack complexity: H
  • Privileges required: N
  • User interaction: R
  • Scope: U
  • Confidentiality: L
  • Integrity: L
  • Availability: N

Temporal​

  • Exploit code madurity: P
  • Remediation level: X
  • Report confidence: X

Result​

  • Vector string: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N/E:P/RL:X/RC:X
  • Score:
    • Base: 3.7
    • Temporal: 3.5
  • Severity:
    • Base: Low
    • Temporal: Low

Code Examples​

Compliant code​

The application uses safe communication SMTP channels

public static void Test(string server){
  string to = "user";
  string from = "user";
  MailMessage message = new MailMessage(from, to);
  message.Subject = "Subject";
  message.Body = @"Body";
  SmtpClient client = new SmtpClient(server);
  client.UseDefaultCredentials = true;
  client.EnableSsl = true;
  client.Send(message);
}

Non compliant code​

The application uses unsafe communication SMTP channels to establish connections

public static void Test(string server) {
  string to = "user";
  string from = "user";
  MailMessage message = new MailMessage(from, to);
  message.Subject = "Subject";
  message.Body = @"Body";
  SmtpClient client = new SmtpClient(server);
  client.UseDefaultCredentials = true;
  client.EnableSsl = false;
  client.Send(message);
}

Requirements​

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