CWE

Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

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ID

CWE-771: Missing Reference to Active Allocated Resource

Weakness ID: 771
Abstraction: Base
Status: Incomplete
Presentation Filter:
+ Description

Description Summary

The software does not properly maintain a reference to a resource that has been allocated, which prevents the resource from being reclaimed.

Extended Description

This does not necessarily apply in languages or frameworks that automatically perform garbage collection, since the removal of all references may act as a signal that the resource is ready to be reclaimed.

+ Time of Introduction
  • Architecture and Design
  • Implementation
+ Common Consequences
ScopeEffect
Availability

Technical Impact: DoS: resource consumption (other)

When allocating resources without limits, an attacker could prevent all other processes from accessing the same type of resource.

+ Likelihood of Exploit

Medium to High

+ Potential Mitigations

Phases: Operation; Architecture and Design

Strategy: Limit Resource Consumption

Use resource-limiting settings provided by the operating system or environment. For example, when managing system resources in POSIX, setrlimit() can be used to set limits for certain types of resources, and getrlimit() can determine how many resources are available. However, these functions are not available on all operating systems.

When the current levels get close to the maximum that is defined for the application (see CWE-770), then limit the allocation of further resources to privileged users; alternately, begin releasing resources for less-privileged users. While this mitigation may protect the system from attack, it will not necessarily stop attackers from adversely impacting other users.

Ensure that the application performs the appropriate error checks and error handling in case resources become unavailable (CWE-703).

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness BaseWeakness Base400Uncontrolled Resource Consumption ('Resource Exhaustion')
Development Concepts (primary)699
Research Concepts (primary)1000
ChildOfCategoryCategory982SFP Secondary Cluster: Failure to Release Resource
Software Fault Pattern (SFP) Clusters (primary)888
ParentOfWeakness VariantWeakness Variant773Missing Reference to Active File Descriptor or Handle
Research Concepts (primary)1000
+ Theoretical Notes

Vulnerability theory is largely about how behaviors and resources interact. "Resource exhaustion" can be regarded as either a consequence or an attack, depending on the perspective. This entry is an attempt to reflect one of the underlying weaknesses that enable these attacks (or consequences) to take place.

+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
Software Fault PatternsSFP14Failure to release resource
+ Maintenance Notes

"Resource exhaustion" (CWE-400) is currently treated as a weakness, although it is more like a category of weaknesses that all have the same type of consequence. While this entry treats CWE-400 as a parent in view 1000, the relationship is probably more appropriately described as a chain.

+ Content History
Submissions
Submission DateSubmitterOrganizationSource
2009-05-13Internal CWE Team
Modifications
Modification DateModifierOrganizationSource
2009-07-27CWE Content TeamMITREInternal
updated Relationships
2010-04-05CWE Content TeamMITREInternal
updated Potential_Mitigations
2011-06-01CWE Content TeamMITREInternal
updated Common_Consequences
2012-05-11CWE Content TeamMITREInternal
updated Relationships
2012-10-30CWE Content TeamMITREInternal
updated Potential_Mitigations
2014-07-30CWE Content TeamMITREInternal
updated Relationships, Taxonomy_Mappings
2017-01-19CWE Content TeamMITREInternal
updated Relationships

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Page Last Updated: January 18, 2017