What is Modification of Assumed-Immutable Data (CWE-471)?

TL;DR: Modification of Assumed-Immutable Data (MAID) allows attackers to alter supposedly immutable data, impacting application integrity. Ensure data validation and integrity checks are in place.

What is Modification of Assumed-Immutable Data (MAID)?

Modification of Assumed-Immutable Data (MAID) (CWE-471) is a type of vulnerability where data assumed to be immutable can be altered by an attacker. As defined by the MITRE Corporation under CWE-471, and classified by the OWASP Foundation under [mapping]…

Quick Summary

Modification of Assumed-Immutable Data (MAID) vulnerabilities allow attackers to modify critical configuration settings or data that are typically assumed to be immutable. This can lead to unexpected states and potential system-wide disruptions.

Jump to: Quick Summary · Modification of Assumed-Immutable Data (MAID) Overview · How Modification of Assumed-Immutable Data (MAID) Works · Business Impact of Modification of Assumed-Immutable Data (MAID) · Modification of Assumed-Immutable Data (MAID) Attack Scenario · How to Detect Modification of Assumed-Immutable Data (MAID) · How to Fix Modification of Assumed-Immutable Data (MAID) · Framework-Specific Fixes for Modification of Assumed-Immutable Data (MAID) · How to Ask AI to Check Your Code for Modification of Assumed-Immutable Data (MAID) · Modification of Assumed-Immutable Data (MAID) Best Practices Checklist · Modification of Assumed-Immutable Data (MAID) FAQ · Vulnerabilities Related to Modification of Assumed-Immutable Data (MAID) · References · Scan Your Own Site

Modification of Assumed-Immutable Data (MAID) Overview

What: MAID is a vulnerability where data assumed to be immutable can be altered by an attacker.

Why it matters: This allows attackers to manipulate critical settings or data, leading to unexpected states and potential system-wide disruptions.

Where it occurs: In web applications, configuration files, environment variables, and other untrusted sources that store or transmit supposedly immutable data.

Who is affected: Applications that rely on unvalidated input for critical configurations or data integrity checks.

Who is NOT affected: Systems already using robust validation mechanisms to ensure data integrity before use.

How Modification of Assumed-Immutable Data (MAID) Works

Root Cause

The root cause lies in inadequate protection mechanisms for data assumed to be immutable, allowing attackers to alter critical settings or data.

Attack Flow

1. Attacker identifies a configuration setting or environment variable that is assumed to be immutable.
2. The attacker modifies this setting through an untrusted source (e.g., HTTP header).
3. The application processes the modified data without proper validation.
4. This leads to unexpected states and potential system-wide disruptions.

Prerequisites to Exploit

• Data must be stored or transmitted through untrusted sources that can modify it.
• Lack of integrity checks for such data before use.

Vulnerable Code

import os

def set_config_value(config_key, config_value):
    # Assume the input is trusted and immutable
    os.environ[config_key] = config_value

This code assumes that config_value is trusted and immutable. However, if an attacker can modify this value through an untrusted source, it leads to unexpected behavior.

Secure Code

import os

def set_config_value(config_key, config_value):
    # Validate the input before setting the environment variable
    allowed_values = ['value1', 'value2']
    if config_value in allowed_values:
        os.environ[config_key] = config_value

The secure code ensures that config_value is validated against a list of expected values before being set as an environment variable.

Business Impact of Modification of Assumed-Immutable Data (MAID)

Integrity

Data tampering and unexpected states can lead to system instability, data corruption, and unauthorized access.

Availability

Critical services may become unavailable if configuration settings are altered by attackers.

Real-world consequences:

• Financial losses due to service disruptions.
• Compliance violations from unauthorized data modifications.
• Damage to reputation from security breaches.

Modification of Assumed-Immutable Data (MAID) Attack Scenario

1. Attacker identifies a critical environment variable that is assumed to be immutable.
2. The attacker modifies this variable through an untrusted source, such as HTTP headers or form fields.
3. The application processes the modified data without proper validation.
4. This leads to unexpected states and potential system-wide disruptions.

How to Detect Modification of Assumed-Immutable Data (MAID)

Manual Testing

• Check for integrity checks on configuration settings and environment variables.
• Validate that untrusted sources cannot modify critical data.

Automated Scanners (SAST / DAST)

Static analysis can detect the absence of validation mechanisms, while dynamic testing can identify actual modifications in runtime environments.

PenScan Detection

PenScan’s scanner engines such as ZAP and Wapiti actively look for vulnerabilities where supposedly immutable data is modified through untrusted sources.

False Positive Guidance

False positives may occur if the input appears risky but is actually safe due to context a scanner cannot determine. Ensure proper validation mechanisms are in place to mitigate this risk.

How to Fix Modification of Assumed-Immutable Data (MAID)

• Implement integrity checks for data stored or transmitted through untrusted sources.
• Validate and sanitize such inputs before use.

Framework-Specific Fixes for Modification of Assumed-Immutable Data (MAID)

Python/Django

def set_config_value(config_key, config_value):
    allowed_values = ['value1', 'value2']
    if config_value in allowed_values:
        os.environ[config_key] = config_value

Java

public void setConfigValue(String configKey, String configValue) {
    List<String> allowedValues = Arrays.asList("value1", "value2");
    if (allowedValues.contains(configValue)) {
        System.setProperty(configKey, configValue);
    }
}

How to Ask AI to Check Your Code for Modification of Assumed-Immutable Data (MAID)

Modification of Assumed-Immutable Data (MAID) Best Practices Checklist

✅ Implement integrity checks for data stored or transmitted through untrusted sources. ✅ Validate and sanitize such inputs before use.

Modification of Assumed-Immutable Data (MAID) FAQ

How do I identify potential MAID vulnerabilities?

Look for any data that is assumed to be immutable but can be modified through untrusted sources. Validate and sanitize such inputs thoroughly.

What are the common attack vectors for Modification of Assumed-Immutable Data (MAID)?

Attackers often exploit environment variables, web application parameters, or HTTP headers to modify supposedly immutable data.

How does MAID affect an application’s integrity?

It allows attackers to manipulate critical configuration settings and data, leading to unexpected states and potential system-wide disruptions.

What steps should I take to prevent Modification of Assumed-Immutable Data (MAID)?

Implement integrity checks for data stored or transmitted through untrusted sources. Ensure that such data is validated against expected values before use.

Can you explain the root cause of Modification of Assumed-Immutable Data (MAID)?

The root cause lies in inadequate protection mechanisms for data assumed to be immutable, allowing attackers to alter critical settings or data.

What are some real-world consequences of a MAID vulnerability?

A successful attack can lead to unauthorized access, data tampering, and system instability, impacting business operations and reputation.

Vulnerabilities Related to Modification of Assumed-Immutable Data (MAID)

| CWE | Name | Relationship | |—|—|—| | CWE-664 | Improper Control of a Resource Through its Lifetime (ChildOf) |

References

• MITRE - CWE-471
• NVD - National Vulnerability Database

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 Modification of Assumed-Immutable Data (MAID) and other risks before an attacker does.