CWE WEAKNESSES  /  CWE-362

CWE-362

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

What it is

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.

A race condition occurs within concurrent environments, and it is effectively a property of a code sequence. Depending on the context, a code sequence may be in the form of a function call, a small number of instructions, a series of program invocations, etc.A race condition violates these properties, which are closely related:- Exclusivity - the code sequence is given exclusive access to the shared resource, i.e., no other code sequence can modify properties of the shared resource before the original sequence has completed execution.- Atomicity - the code sequence is behaviorally atomic, i.e., no other thread or process can concurrently execute the same sequence of instructions (or a subset) against the same resource.A race condition exists when an "interfering code sequence" can still access the shared resource, violating exclusivity.The interfering code sequence could

Impact

Mitigations

• [Architecture and Design] In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
• [Architecture and Design] Use thread-safe capabilities such as the data access abstraction in Spring.
• [Architecture and Design]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).
• [Implementation] When using multithreading and operating on shared variables, only use thread-safe functions.
• [Implementation] 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.
• [Implementation] Use a mutex if available, but be sure to avoid related weaknesses such as CWE-412.
• [Implementation] Avoid double-checked locking (CWE-609) and other implementation errors that arise when trying to avoid the overhead of synchronization.
• [Implementation] 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.

Real-world CVE examples

• CVE-2024-38106 — OS kernel stores sensitive data in improperly locked memory, allowing local users to gain privileges by winning a race condition
• CVE-2022-29527 — Go application for cloud management creates a world-writable sudoers file that allows local attackers to inject sudo rules and escalate privileges to root by wi
• CVE-2021-1782 — Chain: improper locking (CWE-667) leads to race condition (CWE-362), as exploited in the wild per CISA KEV.
• CVE-2021-0920 — Chain: mobile platform race condition (CWE-362) leading to use-after-free (CWE-416), as exploited in the wild per CISA KEV.
• CVE-2020-6819 — Chain: race condition (CWE-362) leads to use-after-free (CWE-416), as exploited in the wild per CISA KEV.
• CVE-2019-18827 — chain: JTAG interface is not disabled (CWE-1191) during ROM code execution, introducing a race condition (CWE-362) to extract encryption keys
• CVE-2019-1161 — Chain: race condition (CWE-362) in anti-malware product allows deletion of files by creating a junction (CWE-1386) and using hard links during the time window i
• CVE-2015-1743 — TOCTOU in sandbox process allows installation of untrusted browser add-ons by replacing a file after it has been verified, but before it is executed
• CVE-2014-8273 — Chain: chipset has a race condition (CWE-362) between when an interrupt handler detects an attempt to write-enable the BIOS (in violation of the lock bit), and
• CVE-2008-5044 — Race condition leading to a crash by calling a hook removal procedure while other activities are occurring at the same time.
• CVE-2008-2958 — chain: time-of-check time-of-use (TOCTOU) race condition in program allows bypass of protection mechanism that was designed to prevent symlink attacks.
• CVE-2008-1570 — chain: time-of-check time-of-use (TOCTOU) race condition in program allows bypass of protection mechanism that was designed to prevent symlink attacks.

Related weaknesses

Source: MITRE CWE. View on cwe.mitre.org →