Base · Medium

CWE-471: Modification of Assumed-Immutable Data (MAID)

The product does not properly protect an assumed-immutable element from being modified by an attacker.

CWE-471 · Base Level ·2 CVEs ·1 Mitigations

Description

The product does not properly protect an assumed-immutable element from being modified by an attacker.

This occurs when a particular input is critical enough to the functioning of the application that it should not be modifiable at all, but it is. Certain resources are often assumed to be immutable when they are not, such as hidden form fields in web applications, cookies, and reverse DNS lookups.

Potential Impact

Integrity

Modify Application Data

Integrity

Unexpected State

Demonstrative Examples

In the code excerpt below, an array returned by a Java method is modified despite the fact that arrays are mutable.
Bad
String[] colors = car.getAllPossibleColors();colors[0] = "Red";

Mitigations & Prevention

Architecture and DesignOperationImplementation

When the data is stored or transmitted through untrusted sources that could modify the data, implement integrity checks to detect unauthorized modification, or store/transmit the data in a trusted location that is free from external influence.

Real-World CVE Examples

CVE IDDescription
CVE-2002-1757Relies on $PHP_SELF variable for authentication.
CVE-2005-1905Gain privileges by modifying assumed-immutable code addresses that are accessed by a driver.

Taxonomy Mappings

  • PLOVER: — Modification of Assumed-Immutable Data

Frequently Asked Questions

What is CWE-471?

CWE-471 (Modification of Assumed-Immutable Data (MAID)) is a software weakness identified by MITRE's Common Weakness Enumeration. It is classified as a Base-level weakness. The product does not properly protect an assumed-immutable element from being modified by an attacker.

How can CWE-471 be exploited?

Attackers can exploit CWE-471 (Modification of Assumed-Immutable Data (MAID)) to modify application data. This weakness is typically introduced during the Implementation, Architecture and Design phase of software development.

How do I prevent CWE-471?

Key mitigations include: When the data is stored or transmitted through untrusted sources that could modify the data, implement integrity checks to detect unauthorized modification, or store/transmit the data in a trusted loc

What is the severity of CWE-471?

CWE-471 is classified as a Base-level weakness (Medium abstraction). It has been observed in 2 real-world CVEs.