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Common Weakness Enumeration

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Home > CWE List > CWE-188: Reliance on Data/Memory Layout (4.16)  
ID

CWE-188: Reliance on Data/Memory Layout

Weakness ID: 188
Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
Abstraction: Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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+ Description
The product makes invalid assumptions about how protocol data or memory is organized at a lower level, resulting in unintended program behavior.
+ Extended Description

When changing platforms or protocol versions, in-memory organization of data may change in unintended ways. For example, some architectures may place local variables A and B right next to each other with A on top; some may place them next to each other with B on top; and others may add some padding to each. The padding size may vary to ensure that each variable is aligned to a proper word size.

In protocol implementations, it is common to calculate an offset relative to another field to pick out a specific piece of data. Exceptional conditions, often involving new protocol versions, may add corner cases that change the data layout in an unusual way. The result can be that an implementation accesses an unintended field in the packet, treating data of one type as data of another type.

+ Common Consequences
Section HelpThis table 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.
Scope Impact Likelihood
Integrity
Confidentiality

Technical Impact: Modify Memory; Read Memory

Can result in unintended modifications or exposure of sensitive memory.
+ Potential Mitigations

Phases: Implementation; Architecture and Design

In flat address space situations, never allow computing memory addresses as offsets from another memory address.

Phase: Architecture and Design

Fully specify protocol layout unambiguously, providing a structured grammar (e.g., a compilable yacc grammar).

Phase: Testing

Testing: Test that the implementation properly handles each case in the protocol grammar.
+ Relationships
Section Help This table 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 "Research Concepts" (CWE-1000)
Nature Type ID Name
ChildOf Pillar Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things. 435 Improper Interaction Between Multiple Correctly-Behaving Entities
ChildOf Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. 1105 Insufficient Encapsulation of Machine-Dependent Functionality
ParentOf Variant Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource. 198 Use of Incorrect Byte Ordering
+ Modes Of Introduction
Section HelpThe different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.
Phase Note
Implementation
+ Applicable Platforms
Section HelpThis listing shows 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.

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

+ Likelihood Of Exploit
Low
+ Demonstrative Examples

Example 1

In this example function, the memory address of variable b is derived by adding 1 to the address of variable a. This derived address is then used to assign the value 0 to b.

(bad code)
Example Language:
void example() {
char a;
char b;
*(&a + 1) = 0;
}

Here, b may not be one byte past a. It may be one byte in front of a. Or, they may have three bytes between them because they are aligned on 32-bit boundaries.


+ Detection Methods

Fuzzing

Fuzz testing (fuzzing) is a powerful technique for generating large numbers of diverse inputs - either randomly or algorithmically - and dynamically invoking the code with those inputs. Even with random inputs, it is often capable of generating unexpected results such as crashes, memory corruption, or resource consumption. Fuzzing effectively produces repeatable test cases that clearly indicate bugs, which helps developers to diagnose the issues.

Effectiveness: High

+ Memberships
Section HelpThis 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.
Nature Type ID Name
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 977 SFP Secondary Cluster: Design
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1399 Comprehensive Categorization: Memory Safety
+ Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID may be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.
+ Taxonomy Mappings
Mapped Taxonomy Name Node ID Fit Mapped Node Name
CLASP Reliance on data layout
+ References
[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 6, "Structure Padding", Page 284. 1st Edition. Addison Wesley. 2006.
[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>. URL validated: 2024-11-17.
+ Content History
+ Submissions
Submission Date Submitter Organization
2006-07-19
(CWE Draft 3, 2006-07-19)
CLASP
+ Modifications
Modification Date Modifier Organization
2008-07-01 Eric Dalci Cigital
updated Time_of_Introduction
2008-09-08 CWE Content Team MITRE
updated Applicable_Platforms, Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings
2009-03-10 CWE Content Team MITRE
updated Relationships
2009-10-29 CWE Content Team MITRE
updated Common_Consequences
2011-03-29 CWE Content Team MITRE
updated Common_Consequences
2011-06-01 CWE Content Team MITRE
updated Common_Consequences
2012-05-11 CWE Content Team MITRE
updated References, Relationships
2012-10-30 CWE Content Team MITRE
updated Potential_Mitigations
2014-06-23 CWE Content Team MITRE
updated Description, Other_Notes
2014-07-30 CWE Content Team MITRE
updated Demonstrative_Examples, Relationships
2019-01-03 CWE Content Team MITRE
updated Description, Relationships
2021-03-15 CWE Content Team MITRE
updated References
2023-01-31 CWE Content Team MITRE
updated Description
2023-04-27 CWE Content Team MITRE
updated Detection_Factors, Relationships, Time_of_Introduction
2023-06-29 CWE Content Team MITRE
updated Mapping_Notes
2024-02-29
(CWE 4.14, 2024-02-29)
CWE Content Team MITRE
updated Demonstrative_Examples
+ Previous Entry Names
Change Date Previous Entry Name
2008-04-11 Reliance on Data Layout
Page Last Updated: November 19, 2024