CVE-2018-25008 in Standard Library
Summary
by MITRE • 04/14/2021
In the standard library in Rust before 1.29.0, there is weak synchronization in the Arc::get_mut method. This synchronization issue can be lead to memory safety issues through race conditions.
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Analysis
by VulDB Data Team • 04/17/2021
The vulnerability identified as CVE-2018-25008 resides within the Rust programming language's standard library, specifically affecting versions prior to 1.29.0. This issue manifests in the Arc::get_mut method which is part of the Atomic Reference Counting implementation used for thread-safe shared ownership of data structures. The problem stems from inadequate synchronization mechanisms that fail to properly protect concurrent access to shared resources, creating a potential pathway for memory safety violations.
The technical flaw in Arc::get_mut represents a race condition vulnerability where multiple threads attempting to access or modify the same Arc instance simultaneously can result in undefined behavior. When get_mut is called on an Arc containing shared data, the method should ensure exclusive access to that data while maintaining thread safety. However, the weak synchronization implementation fails to provide proper atomic operations or memory barriers that would prevent concurrent modifications from corrupting the internal reference count or data structure. This weakness allows for scenarios where one thread might read an inconsistent state while another thread modifies the same Arc instance, leading to potential memory corruption or data races.
The operational impact of this vulnerability extends beyond simple performance degradation to potentially severe memory safety issues that could compromise entire applications. Attackers could exploit this race condition to trigger memory corruption, leading to application crashes, data loss, or potentially more serious security implications if the vulnerable code executes in security-sensitive contexts. The vulnerability is particularly concerning because it affects the standard library's core concurrency primitives, meaning any Rust application relying on Arc for shared ownership could be susceptible to these race conditions, especially in multi-threaded environments where concurrent access patterns are common.
Mitigation strategies for CVE-2018-25008 require immediate version upgrades to Rust 1.29.0 or later where the synchronization issues have been addressed through proper atomic operations and memory ordering constraints. Organizations should conduct comprehensive code reviews to identify any applications still using vulnerable Rust versions and ensure all dependencies are updated accordingly. Additionally, developers should implement defensive programming practices such as avoiding unsafe concurrent access patterns and using proper synchronization primitives like mutexes or channels when sharing data between threads. The vulnerability aligns with CWE-362, which describes race conditions in concurrent programming, and represents a clear violation of the principle of memory safety that Rust aims to guarantee through its ownership model. Security teams should also consider implementing continuous monitoring for vulnerable Rust versions in their software supply chains, as this type of concurrency-related vulnerability can remain undetected for extended periods while still posing significant risks to application stability and security.