What is Improper Neutralization of Delimiters (CWE-140)?

TL;DR: Improper Neutralization of Delimiters (CWE-140) occurs when a product does not neutralize or incorrectly neutralizes delimiters, leading to unexpected state and integrity issues. To fix this vulnerability, implement input validation and output encoding.

At-a-Glance

What is Improper Neutralization of Delimiters?

Improper Neutralization of Delimiters (CWE-140) is a type of vulnerability that occurs when a product does not neutralize or incorrectly neutralizes delimiters. As defined by the MITRE Corporation under CWE-140, and classified by the OWASP Foundation as None available, this vulnerability can lead to unexpected state and integrity issues.

Quick Summary

Improper Neutralization of Delimiters (CWE-140) is a critical vulnerability that occurs when a product does not neutralize or incorrectly neutralizes delimiters. This can lead to unexpected state and integrity issues, making it essential to address this vulnerability promptly. To fix CWE-140, implement input validation and output encoding.

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

Improper Neutralization of Delimiters Overview

What: CWE-140 is a type of vulnerability that occurs when a product does not neutralize or incorrectly neutralizes delimiters.

Why it matters: CWE-140 can lead to unexpected state and integrity issues, making it a critical vulnerability to address.

Where it occurs: CWE-140 typically occurs in web applications, APIs, databases, and file systems.

Who is affected: CWE-140 affects any product that does not neutralize or incorrectly neutralizes delimiters.

Who is NOT affected: Products that correctly neutralize delimiters are not affected by CWE-140.

How Improper Neutralization of Delimiters Works

Root Cause

Improper Neutralization of Delimiters (CWE-140) occurs when a product does not neutralize or incorrectly neutralizes delimiters. This can lead to unexpected state and integrity issues.

Attack Flow

1. An attacker injects malicious input into the system.
2. The system fails to neutralize or correctly neutralize the delimiters in the input.
3. The system processes the input, leading to unexpected state and integrity issues.

Prerequisites to Exploit

• Malicious input must be injected into the system.
• The system must fail to neutralize or correctly neutralize the delimiters in the input.

Vulnerable Code

import os

path = request.form['path']
os.chdir(path)

This code is vulnerable because it fails to validate the path parameter, allowing an attacker to inject malicious input.

Secure Code

import os

path = request.form['path']

if not os.path.abspath(path).startswith(base_dir):
    raise ValueError('Invalid path')

os.chdir(path)

This code is secure because it validates the path parameter before processing it.

Business Impact of Improper Neutralization of Delimiters

Confidentiality: CWE-140 can lead to unauthorized access to sensitive data, compromising confidentiality.

Integrity: CWE-140 can allow an attacker to modify or delete sensitive data, compromising integrity.

Availability: CWE-140 can cause the system to become unavailable, compromising availability.

Real-world business consequences of CWE-140 include:

• Financial losses due to data breaches
• Compliance issues due to regulatory requirements
• Reputation damage due to public disclosure of vulnerabilities

Improper Neutralization of Delimiters Attack Scenario

1. An attacker injects malicious input into the system.
2. The system fails to neutralize or correctly neutralize the delimiters in the input.
3. The system processes the input, leading to unexpected state and integrity issues.

How to Detect Improper Neutralization of Delimiters

Manual Testing

• Review code for potential vulnerabilities
• Test input validation and output encoding
• Use manual testing tools to identify CWE-140

Automated Scanners (SAST / DAST)

• Use automated scanners to identify potential CWE-140 vulnerabilities
• Contrast what static analysis catches with what needs dynamic/runtime testing to find

PenScan Detection

• PenScan’s scanner engines actively test for CWE-140, ensuring you’re aware of potential vulnerabilities before an attacker does.

False Positive Guidance

• Be cautious when identifying CWE-140 due to false positives
• Verify the presence of delimiters and input validation in code

How to Fix Improper Neutralization of Delimiters

• Implement input validation and output encoding
• Use secure libraries or frameworks that handle delimiters correctly

Framework-Specific Fixes for Improper Neutralization of Delimiters

Java

import java.io.File;

public class SecureCode {
    public static void main(String[] args) {
        String path = request.getParameter('path');

        if (!path.startsWith(base_dir)) {
            throw new IllegalArgumentException('Invalid path');
        }

        File file = new File(path);
        // Process the file securely
    }
}

Node.js

const fs = require('fs');

function secureCode() {
    const path = request.getParameter('path');

    if (!path.startsWith(base_dir)) {
        throw new Error('Invalid path');
    }

    const file = new File(path);
    // Process the file securely
}

Python/Django

import os

def secure_code():
    path = request.GET['path']

    if not path.startswith(base_dir):
        raise ValueError('Invalid path')

    file = open(path, 'r')
    # Process the file securely

PHP

function secure_code() {
    $path = $_GET['path'];

    if (!preg_match('/^' . base_dir . '/', $path)) {
        throw new Exception('Invalid path');
    }

    $file = fopen($path, 'r');
    // Process the file securely
}

How to Ask AI to Check Your Code for Improper Neutralization of Delimiters

Review the following Python code block for potential CWE-140 vulnerabilities and rewrite it using input validation:

import os

def secure_code():
    path = request.GET['path']

    if not os.path.abspath(path).startswith(base_dir):
        raise ValueError('Invalid path')

    file = open(path, 'r')
    # Process the file securely

Improper Neutralization of Delimiters Best Practices Checklist

✅ Validate all input parameters. ✅ Use secure libraries or frameworks that handle delimiters correctly. ✅ Implement output encoding to prevent CWE-140.

Improper Neutralization of Delimiters FAQ

How is Improper Neutralization of Delimiters (CWE-140) defined?

Improper Neutralization of Delimiters (CWE-140) occurs when a product does not neutralize or incorrectly neutralizes delimiters.

What are the common consequences of CWE-140?

The common consequences of CWE-140 include unexpected state and integrity issues.

How can I detect CWE-140 in my application?

You can detect CWE-140 using manual testing, automated scanners (SAST / DAST), or PenScan’s detection capabilities.

What are the potential mitigations for CWE-140?

The potential mitigations for CWE-140 include input validation, output encoding, and assuming all input is malicious.

Can you provide an example of vulnerable code for CWE-140?

Yes, here’s an example of vulnerable code for CWE-140: os.chdir(path)

How can I fix CWE-140 in my application?

You can fix CWE-140 by implementing input validation and output encoding.

Are there any framework-specific fixes for CWE-140?

Yes, the framework-specific fixes for CWE-140 include using a secure library or framework that handles delimiters correctly.

Vulnerabilities Related to Improper Neutralization of Delimiters

References

• MITRE CWE-140
• CAPEC-15
• 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 Improper Neutralization of Delimiters and other risks before an attacker does.