CVE-2018-20995 in slice-deque Crate
Summary
by MITRE
An issue was discovered in the slice-deque crate before 0.1.16 for Rust. move_head_unchecked allows memory corruption because deque updates are mishandled.
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Analysis
by VulDB Data Team • 12/04/2023
The vulnerability identified as CVE-2018-20995 affects the slice-deque crate version 0.1.15 and earlier in the Rust programming language ecosystem. This issue represents a critical memory safety flaw that arises from improper handling of deque updates within the move_head_unchecked function. The slice-deque crate is commonly used for implementing efficient double-ended queues with slice-based backing storage, making it a widely adopted component in Rust applications requiring high-performance data structures. The vulnerability stems from the crate's inability to properly validate memory boundaries during head pointer manipulation operations, creating opportunities for memory corruption that can lead to arbitrary code execution or system instability.
The technical root cause of this vulnerability lies in the move_head_unchecked function which operates without proper bounds checking or memory validation mechanisms. When deque operations modify the head pointer position, the function fails to ensure that the new pointer value remains within valid memory boundaries. This flaw creates a classic buffer overread condition where memory locations beyond the intended deque storage can be accessed and modified. The issue is particularly dangerous because it operates at a low level within the memory management system, allowing attackers to potentially overwrite critical data structures or execute malicious code through carefully crafted input sequences. The vulnerability manifests as a memory corruption issue that can be exploited through improper deque manipulation patterns, making it particularly challenging to detect during normal application operation.
The operational impact of CVE-2018-20995 extends beyond simple memory corruption to potentially enable complete system compromise when applications using affected versions of the slice-deque crate are exploited. This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and can be mapped to ATT&CK technique T1059.007 for command and scripting interpreter usage in exploitation scenarios. Applications that rely on deque operations for data processing, particularly those handling untrusted input or performing iterative data manipulation, become vulnerable to remote code execution attacks. The attack surface is broad since the slice-deque crate is used across various Rust projects including web servers, database systems, and network applications that require efficient queue implementations. System administrators and developers must consider that any application using vulnerable versions of this crate could be at risk, regardless of the specific application logic, as the vulnerability exists within the underlying data structure implementation.
Mitigation strategies for CVE-2018-20995 require immediate action to upgrade to version 0.1.16 or later of the slice-deque crate, which contains the necessary fixes for proper memory boundary checking. Organizations should conduct comprehensive inventory audits to identify all applications and dependencies that utilize the affected crate, implementing automated scanning tools to detect vulnerable versions across their software supply chain. The fix implemented in version 0.1.16 addresses the core issue by introducing proper bounds validation before head pointer modifications, ensuring that memory access operations remain within allocated memory regions. Security teams should also implement runtime monitoring for suspicious memory access patterns and consider implementing address space layout randomization techniques to complicate exploitation attempts. Additionally, developers should adopt defensive programming practices including comprehensive input validation, memory safety testing, and regular dependency updates to prevent similar vulnerabilities from emerging in other components of their software systems.