CWE

Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

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ID

CWE-228: Improper Handling of Syntactically Invalid Structure

Weakness ID: 228
Abstraction: Class
Structure: Simple
Status: Incomplete
Presentation Filter:
+ Description
The product does not handle or incorrectly handles input that is not syntactically well-formed with respect to the associated specification.
+ 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.

PhaseNote
Implementation
Architecture and Design
+ 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
Integrity
Availability

Technical Impact: Unexpected State; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)

If an input is syntactically invalid, then processing the input could place the system in an unexpected state that could lead to a crash, consume available system resources or other unintended behaviors.
+ Demonstrative Examples

Example 1

This application has registered to handle a URL when sent an intent:

(bad)
Example Language: Java 
...
IntentFilter filter = new IntentFilter("com.example.URLHandler.openURL");
MyReceiver receiver = new MyReceiver();
registerReceiver(receiver, filter);
...

public class UrlHandlerReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if("com.example.URLHandler.openURL".equals(intent.getAction())) {
String URL = intent.getStringExtra("URLToOpen");
int length = URL.length();
...

}

}

}

The application assumes the URL will always be included in the intent. When the URL is not present, the call to getStringExtra() will return null, thus causing a null pointer exception when length() is called.

+ 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.
+ Notes

Maintenance

This entry needs more investigation. Public vulnerability research generally focuses on the manipulations that generate invalid structure, instead of the weaknesses that are exploited by those manipulations. For example, a common attack involves making a request that omits a required field, which can trigger a crash in some cases. The crash could be due to a named chain such as CWE-690 (Unchecked Return Value to NULL Pointer Dereference), but public reports rarely cover this aspect of a vulnerability.

Maintenance

The validity of input could be roughly classified along "syntactic", "semantic", and "lexical" dimensions. If the specification requires that an input value should be delimited with the "[" and "]" square brackets, then any input that does not follow this specification would be syntactically invalid. If the input between the brackets is expected to be a number, but the letters "aaa" are provided, then the input is syntactically invalid. If the input is a number and enclosed in brackets, but the number is outside of the allowable range, then it is semantically invalid. The inter-relationships between these properties - and their associated weaknesses- need further exploration.
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
PLOVERStructure and Validity Problems
OWASP Top Ten 2004A7CWE More SpecificImproper Error Handling
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
PLOVER
Modifications
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigital
updated Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Description, Maintenance_Notes, Name, Relationships, Relevant_Properties, Taxonomy_Mappings
2009-03-10CWE Content TeamMITRE
updated Description, Name
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2011-06-27CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated Common_Consequences, Relationships
2014-02-18CWE Content TeamMITRE
updated Demonstrative_Examples
2014-07-30CWE Content TeamMITRE
updated Relationships
2017-01-19CWE Content TeamMITRE
updated Relationships
2017-11-08CWE Content TeamMITRE
updated Relevant_Properties
Previous Entry Names
Change DatePrevious Entry Name
2008-09-09Structure and Validity Problems
2009-03-10Failure to Handle Syntactically Invalid Structure

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Page Last Updated: November 14, 2017