CVE-2003-0959 in Linux
Summary
by MITRE
Multiple integer overflows in the 32bit emulation for AMD64 architectures in Linux 2.4 kernel before 2.4.21 allows attackers to cause a denial of service or gain root privileges via unspecified vectors that trigger copy_from_user function calls with improper length arguments.
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Analysis
by VulDB Data Team • 03/14/2017
The vulnerability described in CVE-2003-0959 represents a critical security flaw within the Linux 2.4 kernel's 32-bit emulation subsystem for AMD64 architectures. This issue manifests as multiple integer overflows that occur during the processing of copy_from_user function calls, which are fundamental kernel operations used to transfer data between user space and kernel space. The vulnerability specifically affects systems running Linux kernel versions prior to 2.4.21, creating a window of exposure for attackers who can exploit these flaws to either disrupt system operations or escalate their privileges to root level access. The integer overflow conditions arise from improper handling of length arguments when the kernel attempts to copy data from user-space buffers into kernel memory regions, creating potential for arbitrary code execution or system instability.
The technical implementation of this vulnerability stems from the kernel's 32-bit compatibility layer that enables AMD64 systems to execute 32-bit applications seamlessly. When these systems process certain 32-bit emulation operations, particularly those involving memory copy functions, the kernel fails to properly validate or sanitize input parameters that specify buffer sizes. This failure allows attackers to craft malicious inputs that, when processed through the copy_from_user mechanism, cause integer overflow conditions in the kernel's memory management routines. The flaw operates at the intersection of kernel space and user space operations, leveraging the inherent complexity of system call emulation where 32-bit applications must interact with 64-bit kernel structures. According to CWE classification, this vulnerability maps to CWE-190, Integer Overflow or Wraparound, which specifically addresses issues where integer arithmetic results in values that exceed the maximum representable value for the data type. The vulnerability also aligns with ATT&CK technique T1068, Exploitation for Privilege Escalation, as successful exploitation can lead to root access.
The operational impact of CVE-2003-0959 extends beyond simple denial of service scenarios to encompass potential privilege escalation capabilities that could allow attackers to gain complete system control. When integer overflows occur in kernel memory management functions, they can result in memory corruption that manifests as system crashes or, more dangerously, provide attackers with opportunities to inject and execute arbitrary code with kernel-level privileges. The vulnerability affects systems running Linux 2.4 kernel versions before 2.4.21, making it particularly relevant to older server deployments and embedded systems that may not have received timely security updates. The exploitation vectors remain unspecified in the CVE description, which suggests that multiple attack paths could potentially trigger these integer overflows, increasing the overall risk surface. Organizations running affected kernel versions face significant exposure, as the vulnerability could be exploited by remote attackers without requiring authentication, potentially leading to complete system compromise.
Mitigation strategies for CVE-2003-0959 primarily focus on immediate kernel version updates to 2.4.21 or later, which contain patches addressing the integer overflow conditions in the 32-bit emulation layer. System administrators should prioritize upgrading affected systems to ensure that the kernel includes proper input validation and bounds checking for copy_from_user operations. Additionally, implementing kernel security modules such as grsecurity or PaX can provide additional protection layers against memory corruption exploits, though these solutions require careful configuration to avoid system instability. Network segmentation and access controls should be implemented to limit potential attack vectors, particularly for systems that must continue running older kernel versions temporarily. Regular security audits and vulnerability assessments should be conducted to identify systems running vulnerable kernel versions and ensure timely patch deployment. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date kernel versions and the potential consequences of running unsupported or outdated system software in enterprise environments.