CVE-2020-35892 in simple-slab Crate
Summary
by MITRE • 12/31/2020
An issue was discovered in the simple-slab crate before 0.3.3 for Rust. index() allows an out-of-bounds read.
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Analysis
by VulDB Data Team • 12/31/2020
The vulnerability in the simple-slab crate version 0.3.2 and earlier represents a critical out-of-bounds memory access flaw that can lead to arbitrary code execution or system compromise. This issue affects Rust applications that utilize the slab data structure implementation, which is commonly used for efficient memory management and allocation patterns in systems programming. The vulnerability stems from insufficient bounds checking within the index() method, which fails to validate array or slice indices before accessing underlying memory locations.
The technical flaw manifests when an application calls the index() function on a simple-slab data structure without proper input validation. This allows attackers to provide malicious index values that exceed the valid range of the allocated memory segments, resulting in memory dereferencing beyond intended boundaries. The vulnerability directly maps to CWE-129 Input Validation and Bounds Checking, specifically targeting improper validation of array indices and buffer limits. When the system attempts to access memory at an invalid offset, it can cause segmentation faults, data corruption, or potentially enable attackers to read sensitive information from adjacent memory regions.
The operational impact of this vulnerability extends beyond simple memory corruption scenarios, as it can be exploited in various attack vectors including remote code execution, privilege escalation, and information disclosure. Applications using the affected crate may experience crashes or unpredictable behavior when processing malformed inputs through the slab indexing mechanism. The vulnerability is particularly concerning in systems where the slab implementation handles sensitive data or serves as a core component of memory management. Attackers could leverage this issue to bypass security controls, manipulate application state, or extract confidential information from memory spaces that should remain protected.
Mitigation strategies for this vulnerability include immediate upgrading to simple-slab version 0.3.3 or later, which incorporates proper bounds checking mechanisms in the index() method. Additionally, developers should implement comprehensive input validation at all levels of their applications and employ static analysis tools to identify similar patterns in custom memory management code. The fix should align with industry standards such as those recommended by the Open Web Application Security Project and the Center for Internet Security guidelines for secure coding practices. Organizations should conduct thorough security assessments of their Rust applications that utilize this crate, particularly in production environments where the vulnerability could be exploited to compromise system integrity or confidentiality. Regular dependency updates and security monitoring are essential to prevent exploitation of similar issues in other third-party libraries that may exhibit comparable memory safety vulnerabilities.