CVE-2020-36209 in late-static Crate
Summary
by MITRE • 01/26/2021
An issue was discovered in the late-static crate before 0.4.0 for Rust. Because Sync is implemented for LateStatic with T: Send, a data race can occur.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 02/20/2021
The vulnerability identified as CVE-2020-36209 affects the late-static crate version 0.4.0 and earlier in the Rust programming language ecosystem. This issue stems from improper synchronization mechanisms within the crate's implementation, specifically when the LateStatic type is used with types that implement the Send trait. The fundamental problem lies in the crate's design where it incorrectly assumes that implementing Sync for LateStatic with T: Send is sufficient to prevent concurrent access issues, thereby creating a dangerous assumption about thread safety.
The technical flaw manifests through the improper handling of concurrent access patterns in multi-threaded environments. When a LateStatic instance is created with a type that implements both Send and Sync, the crate's implementation fails to properly enforce memory ordering constraints necessary for safe concurrent access. This creates a classic data race condition where multiple threads can simultaneously read and write to the same memory location without proper synchronization mechanisms, leading to unpredictable behavior and potential memory corruption. The vulnerability directly relates to CWE-362, which describes a race condition vulnerability where two or more threads access shared data concurrently, and at least one of the accesses is a write operation. The improper implementation violates fundamental concurrency principles that Rust's ownership system is designed to prevent.
The operational impact of this vulnerability extends beyond simple performance degradation to potentially serious security implications. In multi-threaded applications that utilize the late-static crate, attackers could exploit this data race to cause memory corruption, arbitrary code execution, or information disclosure. The vulnerability is particularly concerning in systems where the late-static crate is used for configuration management, global state handling, or any scenario where shared mutable state is accessed concurrently. The risk is amplified because Rust's type system typically prevents such issues, but this crate bypasses those protections through its flawed implementation, creating a false sense of security for developers who rely on it for thread-safe operations.
Mitigation strategies for this vulnerability require immediate action from affected parties. The primary recommendation is to upgrade to version 0.4.0 or later of the late-static crate, which contains the necessary fixes for proper synchronization. Organizations should conduct comprehensive code reviews to identify all instances where this crate is used in multi-threaded contexts, particularly examining any code that relies on shared mutable state. Additionally, developers should implement proper synchronization primitives such as mutexes or atomic operations when dealing with shared data that might be accessed concurrently. The remediation process should include thorough testing of concurrent access patterns to ensure that the fix resolves the data race conditions. From an ATT&CK perspective, this vulnerability could be leveraged in initial access or privilege escalation phases, making it particularly dangerous for systems that rely on shared mutable state for critical operations. Organizations should also consider implementing runtime checks or static analysis tools that can detect similar patterns in their codebases to prevent future occurrences of such concurrency issues.