Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

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

Weakness ID: 471
Abstraction: Base
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
The software does not properly protect an assumed-immutable element from being modified by an attacker.
+ Extended Description
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.
+ Relationships

The table(s) below shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.

+ Relevant to the view "Development Concepts" (CWE-699)
+ Modes Of Introduction

The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the software life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

Architecture and Design
+ Applicable Platforms
The listings below show possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.


Class: Language-Independent (Undetermined Prevalence)

+ Common Consequences

The table below specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.


Technical Impact: Modify Application Data

Common data types that are attacked are environment variables, web application parameters, and HTTP headers.

Technical Impact: Unexpected State

+ Demonstrative Examples

Example 1

In the code excerpt below, an array returned by a Java method is modified despite the fact that arrays are mutable.

(bad code)
Example Language: Java 
String[] colors = car.getAllPossibleColors();
colors[0] = "Red";
+ Observed Examples
Relies on $PHP_SELF variable for authentication.
Gain privileges by modifying assumed-immutable code addresses that are accessed by a driver.
+ Potential Mitigations

Phases: Architecture and Design; Operation; Implementation

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.
+ Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.
MemberOfCategoryCategory991SFP Secondary Cluster: Tainted Input to Environment
+ Notes


MAID issues can be primary to many other weaknesses, and they are a major factor in languages that provide easy access to internal program constructs, such as PHP's register_globals and similar features. However, MAID issues can also be resultant from weaknesses that modify internal state; for example, a program might validate some data and store it in memory, but a buffer overflow could overwrite that validated data, leading to a change in program logic.


There are many examples where the MUTABILITY property is a major factor in a vulnerability.
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
PLOVERModification of Assumed-Immutable Data
+ Content History
Submission DateSubmitterOrganization
Modification DateModifierOrganization
2008-07-01Sean EidemillerCigital
added/updated demonstrative examples
2008-07-01Eric DalciCigital
updated Potential_Mitigations, Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Relationships, Other_Notes, Taxonomy_Mappings
2009-07-27CWE Content TeamMITRE
updated Other_Notes
2010-02-16CWE Content TeamMITRE
updated Potential_Mitigations
2010-04-05CWE Content TeamMITRE
updated Related_Attack_Patterns
2010-12-13CWE Content TeamMITRE
updated Related_Attack_Patterns
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated Relationships
2013-02-21CWE Content TeamMITRE
updated Relationships
2013-07-17CWE Content TeamMITRE
updated Relationships
2014-02-18CWE Content TeamMITRE
updated Related_Attack_Patterns
2014-06-23CWE Content TeamMITRE
updated Applicable_Platforms, Common_Consequences, Description, Other_Notes, Potential_Mitigations, Relationship_Notes, Theoretical_Notes, Time_of_Introduction
2014-07-30CWE Content TeamMITRE
updated Relationships
2017-05-03CWE Content TeamMITRE
updated Related_Attack_Patterns

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Page Last Updated: January 18, 2018