CVE-2013-2188 in Red Hat
Summary
by MITRE
A certain Red Hat patch to the do_filp_open function in fs/namei.c in the kernel package before 2.6.32-358.11.1.el6 on Red Hat Enterprise Linux (RHEL) 6 does not properly handle failure to obtain write permissions, which allows local users to cause a denial of service (system crash) by leveraging access to a filesystem that is mounted read-only.
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Analysis
by VulDB Data Team • 05/18/2021
The vulnerability identified as CVE-2013-2188 represents a critical flaw in the Linux kernel's file system handling mechanism within Red Hat Enterprise Linux 6 systems. This issue specifically affects the do_filp_open function located in the fs/namei.c source file, which serves as a fundamental component in the kernel's file system name resolution and file opening operations. The flaw arises from an inadequate error handling mechanism that fails to properly manage scenarios where write permission acquisition encounters failures, creating a potential avenue for system instability.
The technical implementation of this vulnerability stems from the kernel's insufficient validation of file system access permissions during the file opening process. When a local user attempts to access a filesystem that is mounted in read-only mode, the do_filp_open function does not correctly process the permission failure condition that occurs when write access is requested or required. This improper handling causes the kernel to enter an unstable state where it cannot properly manage the file access attempt, leading to a kernel panic and subsequent system crash. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited by any local user with access to the system, regardless of their administrative privileges.
The operational impact of this vulnerability extends beyond simple system instability to encompass complete service disruption and potential data integrity concerns. A local attacker can leverage this weakness to systematically crash the system by repeatedly attempting file operations on read-only mounted filesystems, effectively creating a denial of service condition that can render the entire system unusable. This type of attack is particularly concerning in enterprise environments where system availability is critical, as it can be used to disrupt business operations without requiring elevated privileges or complex exploitation techniques. The vulnerability affects systems running Red Hat Enterprise Linux 6 versions prior to 2.6.32-358.11.1.el6, representing a significant risk to organizations that have not applied the necessary security patches.
Mitigation strategies for this vulnerability primarily focus on immediate patch application and system hardening measures. Organizations should prioritize updating their RHEL 6 systems to the patched kernel version 2.6.32-358.11.1.el6 or later, which contains the necessary corrections to properly handle write permission failures in the do_filp_open function. Additionally, system administrators should review and implement proper file system mount options to minimize exposure, particularly ensuring that unnecessary write access is not granted to read-only filesystems. From a cybersecurity perspective, this vulnerability aligns with CWE-248, which addresses improper exception handling, and can be categorized under ATT&CK technique T1499.004 for network denial of service, though in this case it operates at the kernel level rather than network infrastructure. The vulnerability demonstrates how seemingly minor permission handling flaws can escalate into critical system stability issues, emphasizing the importance of comprehensive kernel security testing and validation.