CWE-362
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
Mitigation
Phase: Architecture and Design
Description:
- In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
Mitigation
Phase: Architecture and Design
Description:
- Use thread-safe capabilities such as the data access abstraction in Spring.
Mitigation
Phase: Architecture and Design
Description:
- Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring.
- Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).
Mitigation
Phase: Implementation
Description:
- When using multithreading and operating on shared variables, only use thread-safe functions.
Mitigation
Phase: Implementation
Description:
- Use atomic operations on shared variables. Be wary of innocent-looking constructs such as "x++". This may appear atomic at the code layer, but it is actually non-atomic at the instruction layer, since it involves a read, followed by a computation, followed by a write.
Mitigation
Phase: Implementation
Description:
- Use a mutex if available, but be sure to avoid related weaknesses such as CWE-412.
Mitigation
Phase: Implementation
Description:
- Avoid double-checked locking (CWE-609) and other implementation errors that arise when trying to avoid the overhead of synchronization.
Mitigation
Phase: Implementation
Description:
- Disable interrupts or signals over critical parts of the code, but also make sure that the code does not go into a large or infinite loop.
Mitigation
Phase: Implementation
Description:
- Use the volatile type modifier for critical variables to avoid unexpected compiler optimization or reordering. This does not necessarily solve the synchronization problem, but it can help.
Mitigation ID: MIT-17
Phases: Architecture and Design, Operation
Strategy: Environment Hardening
Description:
- Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
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-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.