CVE-2021-28035 in stack_dst Crate
Summary
by MITRE • 03/05/2021
An issue was discovered in the stack_dst crate before 0.6.1 for Rust. Because of the push_inner behavior, a drop of uninitialized memory can occur upon a val.clone() panic.
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Analysis
by VulDB Data Team • 03/07/2021
The vulnerability identified as CVE-2021-28035 resides within the stack_dst crate version 0.6.1 and earlier, representing a critical memory safety issue that can lead to undefined behavior and potential exploitation. This flaw specifically manifests in the push_inner function's implementation where improper handling of memory allocation and deallocation creates conditions for uninitialized memory access during cloning operations. The stack_dst crate serves as a memory management utility for Rust applications, facilitating stack-based dynamic storage allocation with specific characteristics for handling variable-sized data structures.
The technical root cause of this vulnerability stems from the improper interaction between the clone operation and the drop mechanism within the stack_dst crate's memory management system. When a val.clone() operation encounters a panic condition, the crate's push_inner behavior triggers a scenario where uninitialized memory gets dropped, creating a potential vector for information disclosure or arbitrary code execution. This issue directly relates to CWE-457, which addresses the use of uninitialized variables, and more specifically to CWE-755, which covers the improper handling of exceptions or errors in memory management. The flaw exploits the fundamental memory safety principles that Rust aims to enforce, creating a scenario where the compiler's safety guarantees are bypassed during exceptional conditions.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially enabling attackers to extract sensitive information from uninitialized memory regions or manipulate program execution flow through carefully crafted input sequences. Since the issue occurs during cloning operations, it affects any application that utilizes the stack_dst crate for dynamic memory management, particularly those handling untrusted input or performing complex data transformations. The vulnerability can be exploited through memory corruption techniques that leverage the uninitialized memory access pattern, potentially allowing for privilege escalation or denial of service conditions depending on the application context.
Mitigation strategies for CVE-2021-28035 require immediate patching of the stack_dst crate to version 0.6.1 or later, which implements proper memory management semantics to prevent uninitialized memory access during panic conditions. Organizations should conduct comprehensive code audits to identify all dependencies on vulnerable versions of the crate and ensure complete remediation across their software supply chain. Additionally, implementing runtime protections such as address space layout randomization and stack canaries can provide defense-in-depth measures against exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1068, which covers 'Exploitation for Privilege Escalation,' as the memory corruption could potentially be leveraged to gain elevated privileges. System administrators should also consider implementing monitoring solutions that detect anomalous memory access patterns or unexpected panic conditions that might indicate exploitation attempts against this vulnerability.