Skip to main content

Use of an insecure channel - Telnet

Description​

Customer information is transmitted over a channel that does not use encryption, so credentials and confidential information can be captured in plain text.

Impact​

Obtain Telnet credentials after a MitM attack.

Recommendation​

Deploy the application over an encrypted communication channel.

Threat​

Anonymous attacker from adjacent network.

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: L
  • Privileges required: N
  • User interaction: R
  • Scope: U
  • Confidentiality: L
  • Integrity: L
  • Availability: N

Temporal​

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

Result​

  • Vector string: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:P/RL:O/RC:X
  • Score:
    • Base: 4.6
    • Temporal: 4.2
  • Severity:
    • Base: Medium
    • Temporal: Medium

Code Examples​

Compliant code​

The application uses an secure channel to transmit data

public static void CreateTestMessage(string server){
  SmtpClient client = new SmtpClient(server);
  client.UseDefaultCredentials = true;
  client.EnableSsl = true;
  client.Send(exampleMessage);
}

Non compliant code​

The application uses an insecure channel to transmit data

public static void CreateTestMessage(string server){
  TcpClient telnet = new TcpClient("10.5.6.59", 23);
  NetworkStream telnetStream = telnet.GetStream();
  StreamWriter output = new StreamWriter(telnetStream);
  StreamReader input = new StreamReader(telnetStream);
  client.Send(ExampleMessage);
}

Requirements​

free trial

Search for vulnerabilities in your apps for free with our automated security testing! Start your 21-day free trial and discover the benefits of our Continuous Hacking Machine Plan. If you prefer a full service that includes the expertise of our ethical hackers, don't hesitate to contact us for our Continuous Hacking Squad Plan.