CWE-145: Improper Neutralization of Section Delimiters

What is Improper Neutralization of Section Delimiters?

• Overview: Improper Neutralization of Section Delimiters (CWE-145) occurs when a software product receives input containing special elements like section delimiters and fails to properly handle them, potentially leading to unexpected behavior when passed to another component.

• Exploitation Methods:

• Attackers can craft input that includes unexpected or malformed delimiters to manipulate the flow or structure of data processing.
• Common attack patterns include injecting additional delimiters to split or join data sections in ways not intended by the application, potentially leading to data leakage or corruption.

• Security Impact:

• Direct consequences of successful exploitation include data corruption, data leakage, or unauthorized access to data sections.
• Potential cascading effects include disruptions in data processing, leading to system instability or denial of service.
• Business impact might involve loss of customer trust, compliance violations, and financial penalties due to data breaches or service outages.

• Prevention Guidelines:

• Specific code-level fixes include validating and sanitizing all inputs to ensure delimiters are correctly handled and escaped.
• Security best practices involve implementing input validation libraries and routines to handle special characters and delimiters safely.
• Recommended tools and frameworks include using security-focused libraries and middleware that automatically handle input neutralization and validation, and conducting regular security audits to identify and fix delimiter handling issues.

Corgea can automatically detect and fix Improper Neutralization of Section Delimiters in your codebase. [Try Corgea free today](https://corgea.app).

Technical Details

Likelihood of Exploit: Not specified

Affected Languages: Not Language-Specific

Affected Technologies: Not specified

Vulnerable Code Example

const fs = require('fs');

function loadConfig(filePath) {
    const config = JSON.parse(fs.readFileSync(filePath, 'utf8'));

    // Vulnerable: Directly using user input to access configuration sections
    // An attacker can exploit this by using section delimiters to access unintended sections
    const userSection = prompt("Enter the configuration section: ");
    if (config[userSection]) {
        console.log(config[userSection]);
    } else {
        console.log("Section not found.");
    }
}

Explanation

In this vulnerable example, the code directly uses user input to access configuration sections without any validation. This can lead to security issues if an attacker inputs section delimiters or special characters to access unintended sections of the configuration.

How to fix Improper Neutralization of Section Delimiters?

To address this issue, sanitize and validate the user input to ensure it conforms to expected patterns and does not include any special characters or section delimiters. Implement a whitelist approach or use regex patterns to enforce strict validation rules, preventing malicious injections.

Fixed Code Example

const fs = require('fs');

function loadConfig(filePath) {
    const config = JSON.parse(fs.readFileSync(filePath, 'utf8'));

    // Fix: Validate user input using regex to ensure it matches a safe pattern
    const userSection = prompt("Enter the configuration section: ");
    
    // Allow only alphanumeric section names
    const isValidSection = /^[a-zA-Z0-9_]+\$/.test(userSection);

    if (isValidSection) {
        if (config[userSection]) {
            console.log(config[userSection]);
        } else {
            console.log("Section not found.");
        }
    } else {
        console.log("Invalid section name. Please use only letters, numbers, and underscores.");
    }
}

Explanation

In the fixed example, a regular expression is used to validate the user input, ensuring it only contains alphanumeric characters and underscores. This prevents malicious input from including section delimiters or other special characters that could be used to exploit the application. By enforcing strict validation rules, the application mitigates the risk of improper neutralization of section delimiters.