CWE-412
Unrestricted Externally Accessible Lock
Incomplete
2006-07-19 00:00 +00:00
2023-06-29 00:00 +00:00
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Unrestricted Externally Accessible Lock
The product properly checks for the existence of a lock, but the lock can be externally controlled or influenced by an actor that is outside of the intended sphere of control.
Extended Description
This prevents the product from acting on associated resources or performing other behaviors that are controlled by the presence of the lock. Relevant locks might include an exclusive lock or mutex, or modifying a shared resource that is treated as a lock. If the lock can be held for an indefinite period of time, then the denial of service could be permanent.
Informations
Modes Of Introduction
Architecture and DesignImplementation
Applicable Platforms
Language
Class: Not Language-Specific (Undetermined)Common Consequences
| Scope | Impact | Likelihood |
|---|---|---|
| Availability | DoS: Resource Consumption (Other) Note: When an attacker can control a lock, the program may wait indefinitely until the attacker releases the lock, causing a denial of service to other users of the program. This is especially problematic if there is a blocking operation on the lock. |
Observed Examples
| Reference | Description |
|---|---|
| Program can not execute when attacker obtains a mutex. | |
| Program can not execute when attacker obtains a lock on a critical output file. | |
| Program can not execute when attacker obtains a lock on a critical output file. | |
| Critical file can be opened with exclusive read access by user, preventing application of security policy. Possibly related to improper permissions, large-window race condition. | |
| Chain: predictable file names used for locking, allowing attacker to create the lock beforehand. Resultant from permissions and randomness. | |
| Chain: Lock files with predictable names. Resultant from randomness. | |
| Product does not check if it can write to a log file, allowing attackers to avoid logging by accessing the file using an exclusive lock. Overlaps unchecked error condition. This is not quite CWE-412, but close. |
Potential Mitigations
Phases : Architecture and Design // ImplementationUse any access control that is offered by the functionality that is offering the lock.
Phases : Architecture and Design // Implementation
Use unpredictable names or identifiers for the locks. This might not always be possible or feasible.
Phases : Architecture and Design
Consider modifying your code to use non-blocking synchronization methods.
Detection Methods
White Box
Automated code analysis techniques might not be able to reliably detect this weakness, since the application's behavior and general security model dictate which resource locks are critical. Interpretation of the weakness might require knowledge of the environment, e.g. if the existence of a file is used as a lock, but the file is created in a world-writable directory.Vulnerability Mapping Notes
Rationale : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.Comments : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.
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. |
Notes
This overlaps Insufficient Resource Pool when the "pool" is of size 1. It can also be resultant from race conditions, although the timing window could be quite large in some cases.Submission
| Name | Organization | Date | Date Release | Version |
|---|---|---|---|---|
| PLOVER | Draft 3 |
Modifications
| Name | Organization | Date | Comment |
|---|---|---|---|
| Eric Dalci | Cigital | updated Potential_Mitigations, Time_of_Introduction | |
| KDM Analytics | added/updated white box definitions | ||
| Veracode | Suggested OWASP Top Ten 2004 mapping | ||
| CWE Content Team | MITRE | updated Common_Consequences, Description, Detection_Factors, Relationships, Observed_Example, Relationship_Notes, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Description | |
| KDM Analytics | Suggested a better name and the minimal relationship with resources regardless of their criticality. | ||
| KDM Analytics | Added a White_Box_Definition and clarified the consequences. | ||
| CWE Content Team | MITRE | updated Common_Consequences, Description, Name, Potential_Mitigations, White_Box_Definitions | |
| CWE Content Team | MITRE | updated Demonstrative_Examples | |
| CWE Content Team | MITRE | updated Common_Consequences, Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Demonstrative_Examples, Relationships | |
| CWE Content Team | MITRE | updated Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Applicable_Platforms, Relationships, White_Box_Definitions | |
| CWE Content Team | MITRE | updated Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Description | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Mapping_Notes |
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