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CWE-662 Detail

CWE-662

Improper Synchronization
Draft
2008-04-11 00:00 +00:00
2024-02-29 00:00 +00:00
CWE Mitre.org

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Improper Synchronization

The product utilizes multiple threads or processes to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes.

Extended Description

Synchronization refers to a variety of behaviors and mechanisms that allow two or more independently-operating processes or threads to ensure that they operate on shared resources in predictable ways that do not interfere with each other. Some shared resource operations cannot be executed atomically; that is, multiple steps must be guaranteed to execute sequentially, without any interference by other processes. Synchronization mechanisms vary widely, but they may include locking, mutexes, and semaphores. When a multi-step operation on a shared resource cannot be guaranteed to execute independent of interference, then the resulting behavior can be unpredictable. Improper synchronization could lead to data or memory corruption, denial of service, etc.

Informations

Modes Of Introduction

Architecture and Design
Implementation

Common Consequences

Scope Impact Likelihood
Integrity
Confidentiality
Other		Modify Application Data, Read Application Data, Alter Execution Logic

Observed Examples

Reference Description
CVE-2021-1782Chain: improper locking (CWE-667) leads to race condition (CWE-362), as exploited in the wild per CISA KEV.
CVE-2009-0935Attacker provides invalid address to a memory-reading function, causing a mutex to be unlocked twice

Potential Mitigations

Phases : Implementation
Use industry standard APIs to synchronize your code.

Vulnerability Mapping Notes

Rationale : This CWE entry is a level-1 Class (i.e., a child of a Pillar). It might have lower-level children that would be more appropriate
Comments : Examine children of this entry to see if there is a better fit

Related Attack Patterns

CAPEC-ID Attack Pattern Name
CAPEC-25 Forced Deadlock
The adversary triggers and exploits a deadlock condition in the target software to cause a denial of service. A deadlock can occur when two or more competing actions are waiting for each other to finish, and thus neither ever does. Deadlock conditions can be difficult to detect.
CAPEC-26 Leveraging Race Conditions
The adversary targets a race condition occurring when multiple processes access and manipulate the same resource concurrently, and the outcome of the execution depends on the particular order in which the access takes place. The adversary can leverage a race condition by "running the race", modifying the resource and modifying the normal execution flow. For instance, a race condition can occur while accessing a file: the adversary can trick the system by replacing the original file with their version and cause the system to read the malicious file.
CAPEC-27 Leveraging Race Conditions via Symbolic Links
This attack leverages the use of symbolic links (Symlinks) in order to write to sensitive files. An attacker can create a Symlink link to a target file not otherwise accessible to them. When the privileged program tries to create a temporary file with the same name as the Symlink link, it will actually write to the target file pointed to by the attackers' Symlink link. If the attacker can insert malicious content in the temporary file they will be writing to the sensitive file by using the Symlink. The race occurs because the system checks if the temporary file exists, then creates the file. The attacker would typically create the Symlink during the interval between the check and the creation of the temporary file.
CAPEC-29 Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions
This attack targets a race condition occurring between the time of check (state) for a resource and the time of use of a resource. A typical example is file access. The adversary can leverage a file access race condition by "running the race", meaning that they would modify the resource between the first time the target program accesses the file and the time the target program uses the file. During that period of time, the adversary could replace or modify the file, causing the application to behave unexpectedly.

Notes

Deeper research is necessary for synchronization and related mechanisms, including locks, mutexes, semaphores, and other mechanisms. Multiple entries are dependent on this research, which includes relationships to concurrency, race conditions, reentrant functions, etc. CWE-662 and its children - including CWE-667, CWE-820, CWE-821, and others - may need to be modified significantly, along with their relationships.

Submission

Name Organization Date Date Release Version
CWE Community 2008-04-11 +00:00 2008-04-11 +00:00 Draft 9

Modifications

Name Organization Date Comment
Eric Dalci Cigital 2008-07-01 +00:00 updated Potential_Mitigations, Time_of_Introduction
CWE Content Team MITRE 2008-09-08 +00:00 updated Relationships
CWE Content Team MITRE 2008-10-14 +00:00 updated Relationships
CWE Content Team MITRE 2008-11-24 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2009-03-10 +00:00 updated Related_Attack_Patterns
CWE Content Team MITRE 2009-05-27 +00:00 updated Relationships
CWE Content Team MITRE 2010-09-27 +00:00 updated Name, Relationships
CWE Content Team MITRE 2010-12-13 +00:00 updated Description, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2011-09-13 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2012-05-11 +00:00 updated Relationships
CWE Content Team MITRE 2012-10-30 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2013-07-17 +00:00 updated Relationships
CWE Content Team MITRE 2014-07-30 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2017-11-08 +00:00 updated Taxonomy_Mappings
CWE Content Team MITRE 2019-01-03 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2019-06-20 +00:00 updated Type
CWE Content Team MITRE 2019-09-23 +00:00 updated Description, Maintenance_Notes, Relationships
CWE Content Team MITRE 2020-02-24 +00:00 updated Description, Relationships
CWE Content Team MITRE 2020-08-20 +00:00 updated Relationships
CWE Content Team MITRE 2020-12-10 +00:00 updated Relationships
CWE Content Team MITRE 2023-01-31 +00:00 updated Description
CWE Content Team MITRE 2023-04-27 +00:00 updated Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes
CWE Content Team MITRE 2023-10-26 +00:00 updated Demonstrative_Examples, Observed_Examples
CWE Content Team MITRE 2024-02-29 +00:00 updated Mapping_Notes

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