|Name ||Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions |
|Summary ||This attack targets a race condition occurring between the time of check (state) for a resource and the time of use of a resource. The typical example is the file access. The attacker can leverage a file access race condition by "running the race", meaning that he 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 attacker could do something such as replace the file and cause an escalation of privilege. |
|Prerequisites ||A resource is access/modified concurrently by multiple processes.
The attacker is able to modify resource.
A race condition exists while accessing a resource. |
|Solutions ||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. |
|CWE ID ||Description |
|CWE-362 ||Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') |
|CWE-366 ||Race Condition within a Thread |
|CWE-367 ||Time-of-check Time-of-use (TOCTOU) Race Condition |
|CWE-368 ||Context Switching Race Condition |
|CWE-370 ||Missing Check for Certificate Revocation after Initial Check |
|CWE-662 ||Improper Synchronization |
|CWE-663 ||Use of a Non-reentrant Function in a Concurrent Context |
|CWE-665 ||Improper Initialization |
|CWE-691 ||Insufficient Control Flow Management |