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Technical information leak - Console functions

Description​

The application uses console functions: log, info, warning. The usage of these functions in productions environments may lead to information leakages and reveal vulnerable methods, technologies, or logic.

Impact​

Gather technical information to craft more complex attack vectors.

Recommendation​

Avoid the use of console functions in production environments. Instead, encourage the use of logs to register errors and exceptional events

Threat​

Authenticated attacker from the Internet.

Expected Remediation Time​

⌚ 15 minutes.

Score​

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

Base​

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

Temporal​

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

Result​

  • Vector string: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:X
  • Score:
    • Base: 3.1
    • Temporal: 2.8
  • Severity:
    • Base: Low
    • Temporal: Low

Code Examples​

Compliant code​

No console functions in production code

using System;
namespace Example {
  public class Example {
    public Test() {
      var text_str = "hello world";
      //Code to do something
    }
  }
}

Non compliant code​

There are console functions in the production code

using System;
namespace Example {
  public class Example {
    public Test() {
      var text_str = "hello world";
      Console.WriteLine($"String: {text_str}");
    }
  }
}

Details​

In front-end programming, JavaScript's Console object provides access to the browser's debugging console1. Arguments passed to log, warn and error methods are visible to the user that is using the website, it's also visible to attackers.

As per Fluid Attacks' criteria2 the application must not disclose internal system information such as stack traces because this information can be leveraged to further exploit other vulnerabilities.

Developers tend to do debugging the following way:

try { /* Business logic code goes here ... */ }
catch (err) {
  console.error(err);
}

But this ends in lots of information that attackers use to better understand the inner workings on the system, aiding them in creating and improving attack vectors.

Error: <rect> attribute x: Expected length, "NaN".
(anonymous) @ cdnjs.cloudflare.com/ajax/libs/d3/5.16.0/d3.min.js:2
Error: <rect> attribute y: Expected length, "NaN".
(anonymous) @ cdnjs.cloudflare.com/ajax/libs/d3/5.16.0/d3.min.js:2
Error: <rect> attribute transform: Expected number, "rotate(NaN, NaN, NaN)".
...

Requirements​

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