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-226: Sensitive Information Uncleared Before Release

Weakness ID: 226
Abstraction: Base
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
The software does not fully clear previously used information in a data structure, file, or other resource, before making that resource available to a party in another control sphere.
+ Extended Description
This typically results from new data that is not as long as the old data, which leaves portions of the old data still available. Equivalent errors can occur in other situations where the length of data is variable but the associated data structure is not. If memory is not cleared after use, it may allow unintended actors to read the data when the memory is reallocated.
+ 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)
+ 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
Architecture and Design
Implementation
Operation
+ 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

(Language-Independent classes): (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.

ScopeImpactLikelihood
Confidentiality

Technical Impact: Read Application Data

+ Observed Examples
ReferenceDescription
Ethernet NIC drivers do not pad frames with null bytes, leading to infoleak from malformed packets.
router does not clear information from DHCP packets that have been previously used
Products do not fully clear memory buffers when less data is stored into the buffer than previous.
Products do not fully clear memory buffers when less data is stored into the buffer than previous.
Products do not fully clear memory buffers when less data is stored into the buffer than previous.
Product does not clear a data structure before writing to part of it, yielding information leak of previously used memory.
Memory not properly cleared before reuse.
+ Weakness Ordinalities
OrdinalityDescription
Resultant
(where the weakness is typically related to the presence of some other weaknesses)
+ Functional Areas
  • Memory Management
  • Networking
+ Affected Resources
  • Memory
+ 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 modification to clarify the differences with CWE-212. The description also combines two problems that are distinct from the CWE research perspective - the inadvertent transfer of information to another sphere, and improper initialization/shutdown. Some of the associated taxonomy mappings reflect these different uses.

Relationship

There is a close association between CWE-226 and CWE-212. The difference is partially that of perspective. CWE-226 is geared towards the final stage of the resource lifecycle, in which the resource is deleted, eliminated, expired, or otherwise released for reuse. Technically, this involves a transfer to a different control sphere, in which the original contents of the resource are no longer relevant. CWE-212, however, is intended for sensitive data in resources that are intentionally shared with others, so they are still active. This distinction is useful from the perspective of the CWE research view (CWE-1000).

Research Gap

Currently frequently found for network packets, but it can also exist in local memory allocation, files, etc.
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
PLOVERSensitive Information Uncleared Before Use
CERT C Secure CodingMEM03-CClear sensitive information stored in reusable resources returned for reuse
Software Fault PatternsSFP23Exposed Data
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
PLOVER
Modifications
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigital
updated Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Relationships, Other_Notes, Relationship_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2008-10-14CWE Content TeamMITRE
updated Relationships
2008-11-24CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2009-03-10CWE Content TeamMITRE
updated Relationships
2009-05-27CWE Content TeamMITRE
updated Relationships
2009-10-29CWE Content TeamMITRE
updated Description, Other_Notes
2010-02-16CWE Content TeamMITRE
updated Applicable_Platforms, Maintenance_Notes, Relationship_Notes
2010-09-27CWE Content TeamMITRE
updated Relationships
2010-12-13CWE Content TeamMITRE
updated Description
2011-06-01CWE Content TeamMITRE
updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-09-13CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2012-05-11CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2014-07-30CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2017-11-08CWE Content TeamMITRE
updated Causal_Nature, Functional_Areas, Relationships, Taxonomy_Mappings
Previous Entry Names
Change DatePrevious Entry Name
2008-04-11Sensitive Information Uncleared Before Use

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Page Last Updated: November 14, 2017