CVE-2011-1479 in Linux
Summary
by MITRE
Double free vulnerability in the inotify subsystem in the Linux kernel before 2.6.39 allows local users to cause a denial of service (system crash) via vectors involving failed attempts to create files. NOTE: this vulnerability exists because of an incorrect fix for CVE-2010-4250.
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Analysis
by VulDB Data Team • 08/16/2024
The vulnerability described in CVE-2011-1479 represents a critical double free error within the Linux kernel's inotify subsystem, affecting versions prior to 2.6.39. This issue emerged as an unintended consequence of a previous fix for CVE-2010-4250, demonstrating how security patches can sometimes introduce new vulnerabilities through incomplete or misguided remediation approaches. The inotify subsystem serves as a kernel mechanism that allows applications to monitor file system events, making it a fundamental component for various system operations including file monitoring, backup utilities, and security applications that rely on real-time file system notifications.
The technical flaw manifests when the inotify subsystem encounters failed file creation attempts, specifically during the process of handling inotify events where memory allocation and deallocation operations become corrupted. In a double free condition, the same memory block gets freed twice, which can lead to memory corruption and unpredictable system behavior. This particular vulnerability occurs in the kernel space where the inotify subsystem manages file system watches and event notifications, creating a scenario where local users can exploit the flawed memory management to trigger the double free condition through carefully crafted file system operations.
The operational impact of this vulnerability extends beyond simple denial of service, as it can potentially lead to system crashes and complete system instability. Local users with minimal privileges can leverage this weakness to cause system-wide disruptions by repeatedly triggering the faulty code path during failed file creation scenarios. The vulnerability's exploitation requires no special privileges beyond normal user access, making it particularly dangerous as it can be abused by any local user to destabilize system operations. System administrators may observe unexpected kernel panics, system lockups, or forced reboots as a result of this vulnerability being exploited.
This vulnerability aligns with CWE-415, which describes double free conditions in software systems, and demonstrates how such flaws can persist even after initial fixes are applied. The ATT&CK framework categorizes this vulnerability under privilege escalation and denial of service tactics, as it allows local users to gain elevated system impact through kernel-level memory corruption. Organizations should prioritize immediate patching of affected systems to address this vulnerability, as the remediation requires updating to kernel versions 2.6.39 or later where the double free condition has been properly resolved. Additionally, system monitoring should include detection of unusual inotify activity patterns that might indicate exploitation attempts, and administrators should implement proper kernel hardening measures to minimize the attack surface. The vulnerability underscores the importance of thorough testing and validation of security patches, as well as the necessity of maintaining up-to-date kernel versions to protect against known vulnerabilities in core system components.