CWE

Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

CWE/SANS Top 25 Most Dangerous Software Errors
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ID

CWE-483: Incorrect Block Delimitation

Weakness ID: 483
Abstraction: Variant
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
The code does not explicitly delimit a block that is intended to contain 2 or more statements, creating a logic error.
+ Extended Description
In some languages, braces (or other delimiters) are optional for blocks. When the delimiter is omitted, it is possible to insert a logic error in which a statement is thought to be in a block but is not. In some cases, the logic error can have security implications.
+ 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 "Research Concepts" (CWE-1000)
NatureTypeIDName
ChildOfClassClass670Always-Incorrect Control Flow Implementation
+ Relevant to the view "Development Concepts" (CWE-699)
NatureTypeIDName
MemberOfCategoryCategory1006Bad Coding Practices
+ 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.

PhaseNote
Implementation
+ 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.

Languages

C (Sometimes Prevalent)

C++ (Sometimes Prevalent)

+ 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.

ScopeImpactLikelihood
Confidentiality
Integrity
Availability

Technical Impact: Alter Execution Logic

This is a general logic error which will often lead to obviously-incorrect behaviors that are quickly noticed and fixed. In lightly tested or untested code, this error may be introduced it into a production environment and provide additional attack vectors by creating a control flow path leading to an unexpected state in the application. The consequences will depend on the types of behaviors that are being incorrectly executed.
+ Likelihood Of Exploit
Low
+ Demonstrative Examples

Example 1

In this example, the programmer has indented the statements to call Do_X() and Do_Y(), as if the intention is that these functions are only called when the condition is true. However, because there are no braces to signify the block, Do_Y() will always be executed, even if the condition is false.

(bad code)
Example Language:
if (condition==true)
Do_X();
Do_Y();

This might not be what the programmer intended. When the condition is critical for security, such as in making a security decision or detecting a critical error, this may produce a vulnerability.

Example 2

In this example, the programmer has indented the Do_Y() statement as if the intention is that the function should be associated with the preceding conditional and should only be called when the condition is true. However, because Do_X() was called on the same line as the conditional and there are no braces to signify the block, Do_Y() will always be executed, even if the condition is false.

(bad code)
Example Language:
if (condition==true) Do_X();
Do_Y();

This might not be what the programmer intended. When the condition is critical for security, such as in making a security decision or detecting a critical error, this may produce a vulnerability.

+ Observed Examples
ReferenceDescription
incorrect indentation of "goto" statement makes it more difficult to detect an incorrect goto (Apple's "goto fail")
+ Potential Mitigations

Phase: Implementation

Always use explicit block delimitation and use static-analysis technologies to enforce this practice.
+ 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.
NatureTypeIDName
MemberOfViewView884CWE Cross-section
MemberOfCategoryCategory977SFP Secondary Cluster: Design
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
CLASPIncorrect block delimitation
+ Content History
Submissions
Submission DateSubmitterOrganization
CLASP
Contributions
Contribution DateContributorOrganization
2010-04-28Michael Koo and Paul BlackNIST
Correction to Demonstrative Examples
Modifications
Modification DateModifierOrganization
2008-07-01Eric DalciCigital
updated Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Applicable_Platforms, Common_Consequences, Description, Relationships, Other_Notes, Taxonomy_Mappings
2009-05-27CWE Content TeamMITRE
updated Demonstrative_Examples
2009-10-29CWE Content TeamMITRE
updated Common_Consequences
2010-06-21CWE Content TeamMITRE
updated Demonstrative_Examples, Description, Other_Notes
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2011-06-27CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated Relationships
2014-06-23CWE Content TeamMITRE
updated Observed_Examples
2014-07-30CWE Content TeamMITRE
updated Relationships
2017-11-08CWE Content TeamMITRE
updated Relationships

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Page Last Updated: January 18, 2018