CVE-2014-0038 in Linux
Summary
by MITRE
The compat_sys_recvmmsg function in net/compat.c in the Linux kernel before 3.13.2, when CONFIG_X86_X32 is enabled, allows local users to gain privileges via a recvmmsg system call with a crafted timeout pointer parameter.
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Analysis
by VulDB Data Team • 11/23/2024
The vulnerability identified as CVE-2014-0038 represents a critical privilege escalation flaw within the Linux kernel's compatibility layer, specifically affecting systems with CONFIG_X86_X32 enabled. This issue resides in the compat_sys_recvmmsg function located in net/compat.c, which handles the recvmmsg system call for 32-bit compatibility mode on 64-bit x86 architectures. The vulnerability stems from improper validation of timeout pointer parameters during the recvmmsg system call execution, creating a pathway for local attackers to escalate their privileges from unprivileged user status to root access. The flaw is particularly concerning because it leverages the x32 ABI (Application Binary Interface) which combines 32-bit user-space with 64-bit kernel interfaces, introducing complex compatibility handling that can lead to memory corruption scenarios.
The technical exploitation of this vulnerability occurs when a local attacker invokes the recvmmsg system call with a specially crafted timeout parameter that points to a memory location containing malicious data. The kernel's compat_sys_recvmmsg function fails to properly validate the timeout pointer, allowing the attacker to manipulate kernel memory structures through the compatibility layer. This misconfiguration enables the attacker to overwrite kernel memory with controlled values, ultimately leading to privilege escalation. The vulnerability specifically affects Linux kernel versions prior to 3.13.2, making systems running these older versions particularly vulnerable to exploitation. The flaw operates at the kernel level and requires no network access, making it a local privilege escalation vulnerability that can be exploited from any user account on the system.
From an operational impact perspective, this vulnerability poses significant risks to system security and integrity as it allows any local user to potentially gain root access without requiring authentication or network connectivity. The exploitation process does not require special privileges beyond normal user access, making it particularly dangerous in multi-user environments where users might have legitimate access to systems. Organizations running affected kernel versions face potential complete system compromise, as attackers can leverage this vulnerability to execute arbitrary code with kernel-level privileges. This capability enables attackers to bypass all standard security controls, modify system files, install backdoors, and establish persistent access to compromised systems. The vulnerability's impact extends beyond individual machines to potentially affect entire network infrastructures if exploited on critical servers.
Mitigation strategies for CVE-2014-0038 primarily involve upgrading to Linux kernel version 3.13.2 or later, which contains the necessary patches to address the vulnerability. System administrators should prioritize patching affected systems and verify that the kernel update has been successfully applied. Additionally, disabling CONFIG_X86_X32 in kernel configuration can prevent exploitation if immediate patching is not feasible, though this may impact applications requiring x32 ABI support. Monitoring systems for signs of exploitation attempts and implementing proper access controls can help detect and prevent unauthorized privilege escalation. Organizations should also consider implementing kernel hardening techniques such as stack canaries, address space layout randomization, and kernel module signing to reduce the overall attack surface. This vulnerability aligns with CWE-121, heap-based buffer overflow, and falls under ATT&CK technique T1068, Valid Accounts, as exploitation requires local user access but results in elevated privileges. The patch for this vulnerability specifically addresses the improper validation of timeout parameters in the compatibility layer, ensuring that kernel memory structures remain protected from malicious manipulation during system call processing.