CWE

Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

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ID

CWE-775: Missing Release of File Descriptor or Handle after Effective Lifetime

Weakness ID: 775
Abstraction: Variant
Status: Incomplete
Presentation Filter:
+ Description

Description Summary

The software does not release a file descriptor or handle after its effective lifetime has ended, i.e., after the file descriptor/handle is no longer needed.

Extended Description

When a file descriptor or handle is not released after use (typically by explicitly closing it), attackers can cause a denial of service by consuming all available file descriptors/handles, or otherwise preventing other system processes from obtaining their own file descriptors/handles.

+ Time of Introduction
  • 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

+ Observed Examples
ReferenceDescription
Chain: anti-virus product encounters a malformed file but returns from a function without closing a file descriptor (CWE-775) leading to file descriptor consumption (CWE-400) and failed scans.
+ 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)
ChildOfCategoryCategory769File Descriptor Exhaustion
Development Concepts (primary)699
Weaknesses for Simplified Mapping of Published Vulnerabilities (primary)1003
ChildOfWeakness BaseWeakness Base772Missing Release of Resource after Effective Lifetime
Research Concepts (primary)1000
ChildOfCategoryCategory982SFP Secondary Cluster: Failure to Release Resource
Software Fault Pattern (SFP) Clusters (primary)888
+ 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
+ References
[REF-7] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 10, "File Descriptor Leaks", Page 582.. 1st Edition. Addison Wesley. 2006.
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
2009-05-13Internal CWE Team
Modifications
Modification DateModifierOrganizationSource
2009-12-28CWE Content TeamMITREInternal
updated Observed_Examples
2010-04-05CWE Content TeamMITREInternal
updated Potential_Mitigations
2011-06-01CWE Content TeamMITREInternal
updated Common_Consequences
2012-05-11CWE Content TeamMITREInternal
updated References, Relationships
2012-10-30CWE Content TeamMITREInternal
updated Potential_Mitigations
2014-07-30CWE Content TeamMITREInternal
updated Relationships, Taxonomy_Mappings
2015-12-07CWE Content TeamMITREInternal
updated Relationships

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Page Last Updated: January 18, 2017