CVE-2003-1023 in Midnight Commander
Summary
by MITRE
Stack-based buffer overflow in vfs_s_resolve_symlink of vfs/direntry.c for Midnight Commander (mc) 4.6.0 and earlier, and possibly later versions, allows remote attackers to execute arbitrary code during symlink conversion.
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Analysis
by VulDB Data Team • 09/03/2019
The vulnerability identified as CVE-2003-1023 represents a critical stack-based buffer overflow affecting the Midnight Commander file manager version 4.6.0 and earlier, with potential impacts extending to later releases. This flaw resides within the vfs_s_resolve_symlink function located in the vfs/direntry.c source file, which handles symbolic link resolution operations. The vulnerability manifests when the application processes symbolic links during file system traversal operations, creating a condition where attacker-controlled input can overflow a fixed-size stack buffer.
The technical implementation of this vulnerability involves the improper handling of symbolic link paths during the resolution process. When Midnight Commander encounters a symbolic link, it attempts to resolve the target path by copying data into a stack buffer without adequate bounds checking. This buffer overflow occurs because the application fails to validate the length of the symbolic link target path against the allocated buffer size, allowing malicious input to overwrite adjacent stack memory. The flaw is particularly dangerous because it can be triggered remotely through network-based file system operations, making it exploitable in scenarios involving remote file systems or network shares.
From an operational perspective, this vulnerability presents a severe security risk as it enables remote code execution capabilities for attackers who can influence the symbolic link resolution process. The attack vector typically involves an attacker placing a maliciously crafted symbolic link in a directory that will be accessed by a victim using Midnight Commander. When the application attempts to resolve the symlink, the buffer overflow can be leveraged to overwrite return addresses and execute arbitrary code with the privileges of the mc process. The impact extends beyond simple privilege escalation as this vulnerability can be exploited across networked file systems, potentially affecting multiple users in shared environments.
The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which specifically addresses buffer overflows occurring in stack memory regions. This classification indicates the flaw's susceptibility to exploitation through manipulation of stack memory layout and control flow. The attack pattern corresponds to techniques described in MITRE ATT&CK framework under T1059 Command and Scripting Interpreter, specifically targeting applications that execute code through interpreter-based mechanisms. The exploitation of this vulnerability requires careful crafting of symbolic link targets to ensure the overflow overwrites critical execution pointers, making it a sophisticated attack requiring precise control over input data.
Mitigation strategies for CVE-2003-1023 involve immediate patching of affected Midnight Commander versions to address the buffer overflow in the symlink resolution function. System administrators should implement network segmentation to limit access to file systems that may be vulnerable to such attacks, particularly in environments where users have the ability to create symbolic links. Input validation mechanisms should be strengthened to prevent untrusted data from being processed in sensitive buffer operations. Additionally, privilege separation techniques should be employed to minimize the impact of successful exploitation attempts, ensuring that the mc application runs with minimal required privileges. Regular security audits of file system operations and symbolic link handling should be conducted to identify potential similar vulnerabilities in other applications that process user-supplied path data.