CWE

Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

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ID

CWE-689: Permission Race Condition During Resource Copy

Weakness ID: 689
Abstraction: Compound
Structure: Composite
Status: Draft
Presentation Filter:
+ Description
The product, while copying or cloning a resource, does not set the resource's permissions or access control until the copy is complete, leaving the resource exposed to other spheres while the copy is taking place.
+ 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)
+ 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

Common examples occur in file archive extraction, in which the product begins the extraction with insecure default permissions, then only sets the final permissions (as specified in the archive) once the copy is complete. The larger the archive, the larger the timing window for the race condition.

This weakness has also occurred in some operating system utilities that perform copies of deeply nested directories containing a large number of files.

This weakness can occur in any type of functionality that involves copying objects or resources in a multi-user environment, including at the application level. For example, a document management system might allow a user to copy a private document, but if it does not set the new copy to be private as soon as the copy begins, then other users might be able to view the document while the copy is still taking place.

+ 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: (Undetermined Prevalence)

Perl: (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
Integrity

Technical Impact: Read Application Data; Modify Application Data

+ Observed Examples
ReferenceDescription
Archive extractor decompresses files with world-readable permissions, then later sets permissions to what the archive specified.
Product inserts a new object into database before setting the object's permissions, introducing a race condition.
Error file has weak permissions before a chmod is performed.
Archive permissions issue using hard link.
Database product creates files world-writable before initializing the setuid bits, leading to modification of executables.
+ Weakness Ordinalities
OrdinalityDescription
Primary
(where the weakness exists independent of other weaknesses)
+ Notes

Research Gap

Under-studied. It seems likely that this weakness could occur in any situation in which a complex or large copy operation occurs, when the resource can be made available to other spheres as soon as it is created, but before its initialization is complete.
+ References
[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 9, "Permission Races", Page 533.. 1st Edition. Addison Wesley. 2006.
+ Content History
Modifications
Modification DateModifierOrganizationSource
2008-09-08CWE Content TeamMITRE
updated Applicable_Platforms, Relationships, Other_Notes, Weakness_Ordinalities
2009-03-10CWE Content TeamMITRE
updated Related_Attack_Patterns
2010-09-27CWE Content TeamMITRE
updated Relationships
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated References
2014-06-23CWE Content TeamMITRE
updated Modes_of_Introduction, Other_Notes
2017-11-08CWE Content TeamMITRE
updated Relationships

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Page Last Updated: November 16, 2017