CVE-2017-1000408 in C Library
Summary
by MITRE
A memory leak in glibc 2.1.1 (released on May 24, 1999) can be reached and amplified through the LD_HWCAP_MASK environment variable. Please note that many versions of glibc are not vulnerable to this issue if patched for CVE-2017-1000366.
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Analysis
by VulDB Data Team • 12/26/2024
The vulnerability identified as CVE-2017-1000408 represents a significant memory leak flaw within the GNU C Library version 2.1.1, which was originally released in 1999. This issue stems from the fundamental design of how glibc handles memory allocation and deallocation processes, particularly when processing the LD_HWCAP_MASK environment variable. The memory leak occurs due to improper handling of hardware capability masks during library initialization and dynamic loading phases. This vulnerability has remained unpatched for over a decade, making it a prime example of legacy code security risks that persist in critical system components. The flaw is particularly concerning because glibc serves as the foundation for virtually all Linux applications, making any vulnerability in this library potentially catastrophic for system stability and security.
The technical exploitation of this vulnerability occurs when the LD_HWCAP_MASK environment variable is set to specific values that trigger the memory leak during program startup or library loading. This environment variable is designed to mask hardware capabilities for compatibility purposes, but in this case, it becomes a vector for memory exhaustion. The flaw operates through a specific code path where allocated memory blocks are not properly freed when processing hardware capability information, leading to gradual memory consumption that can eventually cause system instability or denial of service. This type of vulnerability aligns with CWE-401, which specifically addresses improper management of memory allocation and deallocation, and represents a classic case of resource leak that can be amplified through environmental manipulation.
The operational impact of CVE-2017-1000408 extends far beyond simple memory consumption issues, as it can lead to system-wide instability and service disruption across multiple applications. When exploited, the memory leak can cause applications to gradually consume available system memory until the system becomes unresponsive or crashes entirely. This vulnerability is particularly dangerous in server environments where multiple processes may be simultaneously affected, leading to cascading failures that can compromise entire infrastructure. The amplification factor comes from the fact that a single environment variable setting can trigger memory leaks that compound over time, making this vulnerability particularly effective for sustained denial of service attacks. According to ATT&CK framework, this represents a privilege escalation and denial of service technique that can be leveraged by adversaries to compromise system availability.
Mitigation strategies for this vulnerability require a multi-layered approach that addresses both immediate remediation and long-term architectural improvements. The most effective immediate solution involves patching the glibc library to the latest version that contains the necessary fixes for this memory leak, though this may not be feasible in legacy environments where upgrading is restricted. Organizations should implement monitoring systems that track memory usage patterns and can detect anomalous consumption that might indicate exploitation of this vulnerability. Additionally, proper environment variable validation and sanitization should be implemented to prevent unauthorized manipulation of LD_HWCAP_MASK. System administrators should consider implementing process limits and memory constraints to contain the impact of potential exploitation. The vulnerability also highlights the importance of maintaining up-to-date system libraries and implementing regular security audits to identify similar legacy issues that may persist in critical infrastructure components.