CVE-2023-4205 in Linux
Summary
by MITRE • 08/07/2023
An out-of-bounds memory access flaw was found in the Linux kernel’s do_journal_end function when the fails array-index-out-of-bounds in fs/reiserfs/journal.c could happen. This flaw allows a local user to crash the system.
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Analysis
by VulDB Data Team • 08/07/2023
The vulnerability identified as CVE-2023-4205 represents a critical out-of-bounds memory access flaw within the Linux kernel's reiserfs file system implementation. This issue resides in the do_journal_end function located in the fs/reiserfs/journal.c source file, where an array index becomes invalid during journal processing operations. The flaw stems from inadequate bounds checking mechanisms that fail to validate array access parameters before executing memory operations. Such vulnerabilities typically arise from insufficient input validation and improper boundary condition enforcement in kernel space code where memory corruption can lead to system instability or compromise.
The technical exploitation of this vulnerability occurs when a local user executes specific operations on a reiserfs file system that trigger the problematic code path. During journal end processing, the fails array is accessed with an index that exceeds the allocated array boundaries, resulting in memory corruption. This memory access violation can manifest as a kernel panic, system crash, or more insidiously, allow for potential privilege escalation or information disclosure depending on the memory layout and access patterns. The flaw specifically targets the journaling mechanism used by reiserfs to ensure data consistency during file system operations, making it particularly dangerous in environments where this file system is actively used.
The operational impact of CVE-2023-4205 extends beyond simple system crashes, as local users can leverage this vulnerability to disrupt system availability and potentially gain unauthorized access to system resources. Attackers with local access can exploit this flaw to cause denial of service conditions that may affect critical system operations or services running on affected systems. The vulnerability's classification aligns with CWE-129, which addresses improper validation of array indices, and falls under ATT&CK technique T1068, specifically targeting local privilege escalation through kernel vulnerabilities. Systems running Linux kernels with reiserfs file systems are at risk, particularly in environments where local user access is not properly restricted or where system stability is paramount for operations.
Mitigation strategies for CVE-2023-4205 should prioritize immediate kernel updates from trusted sources to address the underlying memory access violation. System administrators should implement strict access controls to limit local user privileges and monitor for suspicious activities that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper bounds checking in kernel space code and highlights the necessity of thorough code reviews and security testing for file system implementations. Organizations should also consider implementing intrusion detection systems to monitor for abnormal kernel behavior patterns that could indicate exploitation attempts, while maintaining regular security assessments of their kernel configurations and file system usage to prevent similar vulnerabilities from emerging in other components of the operating system stack.