CVE-2022-1508 in Linux
Summary
by MITRE • 08/31/2022
An out-of-bounds read flaw was found in the Linux kernel’s io_uring module in the way a user triggers the io_read() function with some special parameters. This flaw allows a local user to read some memory out of bounds.
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Analysis
by VulDB Data Team • 10/10/2022
The vulnerability identified as CVE-2022-1508 represents a critical out-of-bounds read flaw within the Linux kernel's io_uring subsystem, which is a high-performance asynchronous I/O interface designed to handle large volumes of I/O operations efficiently. This issue specifically manifests when a user invokes the io_read() function with particular parameter configurations that bypass normal input validation mechanisms. The io_uring module, which operates under the Common Weakness Enumeration framework as CWE-129, implements a sophisticated event-driven I/O processing model that has become increasingly prevalent in modern Linux systems for handling concurrent operations. The flaw exists at the kernel level, making it particularly dangerous as it operates within the most privileged execution context where memory access controls are normally most stringent.
The technical implementation of this vulnerability stems from inadequate bounds checking within the io_uring subsystem's handling of read operations. When a user-space application triggers io_read() with malformed or specially crafted parameters, the kernel's input validation fails to properly verify array indices or buffer boundaries before accessing memory locations. This particular flaw falls under the ATT&CK framework's technique T1068, which covers 'Local Privilege Escalation' through kernel exploits, as it allows local users to access memory regions that should normally be protected. The vulnerability enables an attacker to read memory contents that extend beyond the intended buffer boundaries, potentially exposing sensitive kernel data structures, credential information, or other confidential data that resides in adjacent memory locations. The out-of-bounds memory access occurs during the processing of I/O completion events, where the kernel fails to validate parameter inputs before performing memory dereferences.
The operational impact of CVE-2022-1508 extends beyond simple information disclosure, as it creates a potential pathway for more severe security breaches within kernel space. While the immediate effect is limited to reading arbitrary memory locations, this vulnerability could be leveraged by attackers to discover kernel memory layouts, extract sensitive information such as cryptographic keys or session tokens, or potentially aid in developing more sophisticated exploits. The flaw affects systems running Linux kernel versions where io_uring is implemented and actively used, particularly those with applications that rely heavily on asynchronous I/O operations. This vulnerability demonstrates the complexity of modern kernel subsystems and how seemingly minor input validation gaps can create significant security risks. The local nature of this vulnerability means that an attacker must already have user-level access to the system, but the potential for privilege escalation or information leakage makes it particularly concerning for environments where multiple users share systems or where the kernel is exposed to untrusted applications.
Mitigation strategies for CVE-2022-1508 should focus on both immediate patching and operational hardening measures. System administrators should prioritize updating to kernel versions that contain the appropriate fixes, which typically involve implementing proper bounds checking within the io_uring subsystem's parameter validation routines. The patch addresses the root cause by ensuring that all input parameters to io_read() are properly validated before memory access operations occur, aligning with security best practices outlined in the NIST Cybersecurity Framework. Organizations should also consider implementing additional monitoring and logging of io_uring operations to detect anomalous behavior patterns that might indicate exploitation attempts. Network segmentation and privilege separation can help limit the potential impact of successful exploitation, while regular security assessments should verify that no other similar vulnerabilities exist within the kernel's I/O handling subsystems. The vulnerability serves as a reminder of the importance of rigorous input validation in kernel space operations and the need for comprehensive security testing of critical subsystems like io_uring that handle high-volume I/O operations in production environments.