What is Covert Timing Channel (CWE-385)?

TL;DR: Covert Timing Channel (CWE-385) is a security misconfiguration that conveys information by modulating system behavior over time, allowing a program to infer protected information. To fix it, implement artificial delays and remove information from attackers.

At-a-Glance Table

What is Covert Timing Channel?

Covert Timing Channel (CWE-385) is a type of security misconfiguration that occurs when an application conveys information by modulating system behavior over time. As defined by the MITRE Corporation under CWE-385, and classified by the OWASP Foundation under No official mapping…

Quick Summary

A covert timing channel can lead to confidentiality and other impacts, such as information exposure. It’s essential to identify and mitigate this issue to prevent potential attacks.

Jump to: What is Covert Timing Channel? · Quick Summary · Covert Timing Channel Overview · How Covert Timing Channel Works · Business Impact of Covert Timing Channel · Covert Timing Channel Attack Scenario · How to Detect Covert Timing Channel · How to Fix Covert Timing Channel · Framework-Specific Fixes for Covert Timing Channel · How to Ask AI to Check Your Code for Covert Timing Channel · Covert Timing Channel Best Practices Checklist · Covert Timing Channel FAQ · Vulnerabilities Related to Covert Timing Channel · References · Scan Your Own Site

Covert Timing Channel Overview

What: A covert timing channel conveys information by modulating system behavior over time.

Why it matters: This vulnerability can lead to confidentiality and other impacts, such as information exposure.

Where it occurs: In web applications and network protocols.

Who is affected: Anyone who uses or interacts with the application.

Who is NOT affected: Those who do not use or interact with the application.

How Covert Timing Channel Works

Root Cause

A covert timing channel conveys information by modulating system behavior over time, allowing a program to infer protected information.

Attack Flow

1. The attacker sends a request to the application.
2. The application processes the request and takes some action based on the input.
3. The attacker observes the response time of the application and infers protected information.

Prerequisites to Exploit

• The attacker must be able to send requests to the application.
• The application must process the requests in a way that allows the attacker to infer protected information.

Vulnerable Code

import time

def process_request(request):
    # Simulate some processing time based on the input
    if request['input'] == 'secret':
        time.sleep(1)
    else:
        time.sleep(0.5)

process_request({'input': 'secret'})

The vulnerable code above simulates some processing time based on the input, allowing an attacker to infer protected information.

Secure Code

import time

def process_request(request):
    # Introduce a delay between operations
    time.sleep(1)
    # Process the request as usual
    if request['input'] == 'secret':
        print('Protected information accessed')
    else:
        print('No protected information accessed')

process_request({'input': 'secret'})

The secure code above introduces a delay between operations, making it harder for attackers to infer protected information.

Business Impact of Covert Timing Channel

Confidentiality: The covert timing channel can lead to confidentiality impacts, such as information exposure.

• Financial: Companies may lose sensitive data or intellectual property.
• Compliance: Organizations may face regulatory penalties for failing to protect sensitive information.
• Reputation: Businesses may suffer from damage to their reputation due to security breaches.

Covert Timing Channel Attack Scenario

1. The attacker sends a request to the application with some input.
2. The application processes the request and takes some action based on the input.
3. The attacker observes the response time of the application and infers protected information.

How to Detect Covert Timing Channel

Manual Testing

• Use a tool like Burp Suite or ZAP to simulate requests and observe response times.
• Look for inconsistencies in response times that may indicate a covert timing channel.

Automated Scanners (SAST/DAST)

• Use tools like Snyk or CodeScan to identify potential vulnerabilities.
• These tools can help detect covert timing channels by analyzing code and identifying patterns that may indicate this vulnerability.

PenScan Detection

• PenScan’s scanner engines actively test for this issue.
• Our scanners can help identify potential vulnerabilities and provide recommendations for remediation.

False Positive Guidance

• Be cautious when interpreting results, as false positives are possible.
• Use context and additional testing to confirm the presence of a covert timing channel.

How to Fix Covert Timing Channel

• Implement artificial delays between operations.
• Remove information from attackers that may be used to infer protected information.

Framework-Specific Fixes for Covert Timing Channel

Java

import java.util.concurrent.TimeUnit;

public class SecureCode {
    public static void processRequest(String input) {
        // Introduce a delay between operations
        TimeUnit.SECONDS.sleep(1);
        // Process the request as usual
        if (input.equals("secret")) {
            System.out.println("Protected information accessed");
        } else {
            System.out.println("No protected information accessed");
        }
    }

    public static void main(String[] args) {
        processRequest("secret");
    }
}

Node.js

const secureCode = (input) => {
  // Introduce a delay between operations
  setTimeout(() => {
    // Process the request as usual
    if (input === "secret") {
      console.log("Protected information accessed");
    } else {
      console.log("No protected information accessed");
    }
  }, 1000);
};

secureCode("secret");

How to Ask AI to Check Your Code for Covert Timing Channel

Review the following [language] code block for potential CWE-385 Covert Timing Channel vulnerabilities and rewrite it using artificial delays.

import time

def process_request(request):
    # Simulate some processing time based on the input
    if request['input'] == 'secret':
        time.sleep(1)
    else:
        time.sleep(0.5)

process_request({'input': 'secret'})

Covert Timing Channel Best Practices Checklist

✅ Implement artificial delays between operations. ✅ Remove information from attackers that may be used to infer protected information.

Covert Timing Channel FAQ

How does a covert timing channel work?

A covert timing channel conveys information by modulating system behavior over time, allowing a program to infer protected information.

What are the common consequences of a covert timing channel?

The common consequences include confidentiality and other impacts, such as information exposure.

How can I detect a covert timing channel in my application?

You can use manual testing, automated scanners (SAST/DAST), or PenScan’s detection capabilities to identify potential vulnerabilities.

What are the best practices for preventing a covert timing channel?

Implementing artificial delays and removing information from attackers are some strategies that can help mitigate this vulnerability.

Can you give an example of how to fix a covert timing channel in Java?

Yes, you can use the Thread.sleep() method to introduce a delay between operations, making it harder for attackers to infer protected information.

What are some related vulnerabilities to a covert timing channel?

CWE-514: Covert Channel is a more general category that encompasses this vulnerability.

How can I ask an AI coding assistant to check my code for potential covert timing channel vulnerabilities?

You can use the following prompt: “Review the following [language] code block for potential CWE-385 Covert Timing Channel vulnerabilities and rewrite it using artificial delays.”

What are some best practices for preventing a covert timing channel in web applications?

Implementing artificial delays, removing information from attackers, and using secure coding practices can help mitigate this vulnerability.

Vulnerabilities Related to Covert Timing Channel

References

• MITRE CWE-385
• CAPEC-462
• NVD

Scan Your Own Site

Manual code review catches what you know to look for. An automated scan catches what you didn’t. Scan your own website using PenScan to find Covert Timing Channel and other risks before an attacker does.