CAPEC Definitions / CAPEC-29
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.
Extended Description
No Extended Description.
Mitigations
Use safe libraries to access resources such as files.
Be aware that improper use of access function calls such as chown(), tempfile(), chmod(), etc. can cause a race condition.
Use synchronization to control the flow of execution.
Use static analysis tools to find race conditions.
Pay attention to concurrency problems related to the access of resources.
Relationships with other CAPECs
CAPEC-26: Leveraging Race Conditions
Prerequisites
A resource is access/modified concurrently by multiple processes.
The adversary is able to modify resource.
A race condition exists while accessing a resource.
Related Weaknesses
CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
CWE-368: Context Switching Race Condition
CWE-366: Race Condition within a Thread
CWE-370: Missing Check for Certificate Revocation after Initial Check
CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-662: Improper Synchronization
CWE-691: Insufficient Control Flow Management
CWE-663: Use of a Non-reentrant Function in a Concurrent Context
CWE-665: Improper Initialization
