What is Improper Preservation of Permissions (CWE-281)?

TL;DR: Improper Preservation of Permissions (CWE-281) occurs when a product fails to preserve permissions or incorrectly preserves them, leading to less restrictive permissions than intended.

At-a-Glance Table

What is Improper Preservation of Permissions?

Improper Preservation of Permissions (CWE-281) is a type of Broken Access Control vulnerability that occurs when a product fails to preserve permissions or incorrectly preserves them, leading to less restrictive permissions than intended.

As defined by the MITRE Corporation under CWE-281, and classified by the OWASP Foundation under A01:2025 - Broken Access Control, Improper Preservation of Permissions is a critical vulnerability that can result in unauthorized access and modification of sensitive data.

Quick Summary

Improper Preservation of Permissions (CWE-281) occurs when a product fails to preserve permissions or incorrectly preserves them, leading to less restrictive permissions than intended. This can result in unauthorized access and modification of sensitive data, leading to financial losses and reputational damage.

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

Improper Preservation of Permissions Overview

What

Improper Preservation of Permissions (CWE-281) occurs when a product fails to preserve permissions or incorrectly preserves them, leading to less restrictive permissions than intended.

Why it matters

Improper Preservation of Permissions can result in unauthorized access and modification of sensitive data, leading to financial losses and reputational damage.

Where it occurs

Improper Preservation of Permissions can occur in any system that uses permissions, including operating systems, applications, and services.

Who is affected

Any user or process that has access to the system or application can be affected by Improper Preservation of Permissions.

Who is NOT affected

Users who do not have access to the system or application are not affected by Improper Preservation of Permissions.

How Improper Preservation of Permissions Works

Root Cause

The root cause of Improper Preservation of Permissions is a failure to preserve permissions or incorrect preservation of them, leading to less restrictive permissions than intended.

Attack Flow

1. An attacker gains access to the system or application.
2. The attacker exploits the vulnerability in Improper Preservation of Permissions.
3. The attacker gains unauthorized access and modification of sensitive data.

Prerequisites to Exploit

• The attacker must have access to the system or application.
• The vulnerability in Improper Preservation of Permissions must be present.

Vulnerable Code

// Vulnerable code: failing to preserve permissions
public void copyFile(String source, String destination) {
    File file = new File(source);
    if (file.exists()) {
        // Failing to preserve permissions
        file.setReadable(true);
        file.setWritable(true);
    }
}

The vulnerable code fails to preserve permissions when copying a file.

Secure Code

// Secure code: preserving permissions
public void copyFile(String source, String destination) {
    File file = new File(source);
    if (file.exists()) {
        // Preserving permissions
        file.setReadable(true);
        file.setWritable(false);
    }
}

The secure code preserves permissions when copying a file.

Business Impact of Improper Preservation of Permissions

Confidentiality

Improper Preservation of Permissions can result in unauthorized access to sensitive data, leading to confidentiality breaches.

• Financial losses due to data breaches
• Reputational damage due to data breaches

Integrity

Improper Preservation of Permissions can result in unauthorized modification of sensitive data, leading to integrity breaches.

• Financial losses due to data breaches
• Reputational damage due to data breaches

Availability

Improper Preservation of Permissions can result in denial-of-service attacks, leading to availability breaches.

• Financial losses due to downtime
• Reputational damage due to downtime

Improper Preservation of Permissions Attack Scenario

1. An attacker gains access to the system or application.
2. The attacker exploits the vulnerability in Improper Preservation of Permissions.
3. The attacker gains unauthorized access and modification of sensitive data.

How to Detect Improper Preservation of Permissions

Manual Testing

• Review code for improper preservation of permissions
• Test code with manual testing tools

Automated Scanners (SAST/DAST)

• Use SAST/DAST tools to detect vulnerabilities in code
• Contrast what static analysis catches vs. what needs dynamic/runtime testing to find

PenScan Detection

• PenScan’s scanner engines actively test for this issue.
• Detects vulnerabilities in code.

False Positive Guidance

• Be cautious of false positives due to similar-looking code patterns.
• Review code manually to confirm findings.

How to Fix Improper Preservation of Permissions

• Ensure that permissions are properly preserved when copying, restoring, or sharing objects.
• Use permission management tools to manage permissions correctly.

Framework-Specific Fixes for Improper Preservation of Permissions

Java

// Secure code: preserving permissions in Java
public void copyFile(String source, String destination) {
    File file = new File(source);
    if (file.exists()) {
        // Preserving permissions
        file.setReadable(true);
        file.setWritable(false);
    }
}

Node.js

// Secure code: preserving permissions in Node.js
const fs = require('fs');
const file = fs.createReadStream(source);
file.pipe(fs.createWriteStream(destination));
file.on('close', () => {
  // Preserving permissions
  fs.chmodSync(destination, 0o644);
});

Python/Django

# Secure code: preserving permissions in Python/Django
from django.core.files.storage import FileSystemStorage
storage = FileSystemStorage()
file = storage.open(source)
data = file.read()
file.close()
destination_file = open(destination, 'wb')
destination_file.write(data)
destination_file.close()
# Preserving permissions
os.chmod(destination, 0o644)

PHP

// Secure code: preserving permissions in PHP
$sourceFile = fopen($source, 'r');
$destinationFile = fopen($destination, 'w');
while (($line = fgets($sourceFile)) !== false) {
    fwrite($destinationFile, $line);
}
fclose($sourceFile);
fclose($destinationFile);
# Preserving permissions
chmod($destination, 0o644);

How to Ask AI to Check Your Code for Improper Preservation of Permissions

To ask an AI coding assistant to check your code for Improper Preservation of Permissions, you can use the following prompt:

“Review the following [language] code block for potential CWE-281 Improper Preservation of Permissions vulnerabilities and rewrite it using permission management tools: [paste code here].”

Improper Preservation of Permissions Best Practices Checklist

✅ Ensure that permissions are properly preserved when copying, restoring, or sharing objects. ✅ Use permission management tools to manage permissions correctly. ✅ Regularly review code for potential CWE-281 Improper Preservation of Permissions vulnerabilities.

Improper Preservation of Permissions FAQ

How does Improper Preservation of Permissions occur?

Improper Preservation of Permissions occurs when a product fails to preserve permissions or incorrectly preserves them, leading to less restrictive permissions than intended.

What are the common consequences of Improper Preservation of Permissions?

The common consequences of Improper Preservation of Permissions include unauthorized access and modification of sensitive data.

How can I prevent Improper Preservation of Permissions?

To prevent Improper Preservation of Permissions, ensure that permissions are properly preserved when copying, restoring, or sharing objects.

What is the business impact of Improper Preservation of Permissions?

The business impact of Improper Preservation of Permissions includes financial losses due to data breaches and reputational damage.

How can I detect Improper Preservation of Permissions in my code?

You can detect Improper Preservation of Permissions using manual testing, automated scanners (SAST/DAST), or PenScan’s detection capabilities.

What are the related weaknesses to Improper Preservation of Permissions?

The related weaknesses to Improper Preservation of Permissions include CWE-732: Incorrect Permission Assignment for Critical Resource and CWE-732: Incorrect Permission Assignment for Critical Resource.

How can I fix Improper Preservation of Permissions in my code?

To fix Improper Preservation of Permissions, ensure that permissions are properly preserved when copying, restoring, or sharing objects.

Vulnerabilities Related to Improper Preservation of Permissions

References

• MITRE CWE-281
• OWASP A01:2025 - Broken Access Control
• 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 Preservation of Permissions and other risks before an attacker does.