CVE-2021-26306 in raw-cpuid Crate
Summary
by MITRE • 01/29/2021
An issue was discovered in the raw-cpuid crate before 9.0.0 for Rust. It has unsound transmute calls within as_string() methods.
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Analysis
by VulDB Data Team • 02/21/2021
The vulnerability identified as CVE-2021-26306 resides within the raw-cpuid crate version 9.0.0 and earlier, representing a critical flaw in Rust-based systems that handle CPU identification and feature detection. This crate serves as a low-level interface for accessing CPUID information through direct hardware interaction, making it a critical component in systems requiring precise hardware capabilities assessment. The issue manifests in the as_string() methods where unsound transmute operations are employed, creating potential for undefined behavior and memory safety violations within Rust applications that utilize this crate. Such vulnerabilities are particularly dangerous in systems where memory corruption could lead to privilege escalation or arbitrary code execution.
The technical flaw stems from the use of transmute operations that bypass Rust's type system guarantees, specifically in the context of converting CPU identification data into string representations. When the as_string() methods execute unsound transmutes, they create scenarios where memory layouts may not align with expected types, leading to potential memory corruption or access violations. This vulnerability directly relates to CWE-467, which addresses the use of potentially dangerous functions, and more specifically to CWE-704, concerning incorrect type conversions. The unsound nature of these transmute operations violates Rust's fundamental safety guarantees, potentially allowing attackers to exploit memory layout assumptions and cause unpredictable behavior in applications.
The operational impact of this vulnerability extends beyond simple memory corruption, as applications relying on the raw-cpuid crate for hardware feature detection may experience system instability, crashes, or even security breaches. In environments where CPU identification is used for security decisions, such as in virtualization contexts or systems implementing hardware-based security features, this vulnerability could enable attackers to bypass security measures or escalate privileges. The risk is amplified in systems where the crate is used in conjunction with other security-sensitive components, as the memory corruption could propagate through the system and compromise overall security posture. This vulnerability aligns with ATT&CK technique T1059.001, which covers command and scripting interpreter usage, particularly in scenarios where memory corruption could enable privilege escalation.
Mitigation strategies for CVE-2021-26306 require immediate updates to the raw-cpuid crate to version 9.0.0 or later, which addresses the unsound transmute operations through proper type conversion methods. Organizations should conduct thorough code reviews to identify any other instances where similar transmute operations might exist within their dependency tree, particularly in low-level hardware interaction libraries. System administrators should prioritize patching affected systems and monitor for any unusual behavior that might indicate exploitation attempts. The remediation process should include updating all dependencies that rely on vulnerable versions of the crate, ensuring that no legacy components remain that could expose systems to this vulnerability. Additionally, implementing runtime checks and memory protection mechanisms can provide additional defense-in-depth measures against potential exploitation attempts that might arise from similar memory safety issues in other components.