CVE-2018-11097 in cstring
Summary
by MITRE
An issue was discovered in cloudwu/cstring through 2016-11-09. There is a memory leak vulnerability that could lead to a program crash.
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Analysis
by VulDB Data Team • 02/05/2020
The vulnerability identified as CVE-2018-11097 resides within the cloudwu/cstring library, a C string manipulation utility that was active until November 9, 2016. This memory leak vulnerability represents a critical flaw in the library's resource management capabilities, where allocated memory blocks are not properly released back to the system after use. The issue manifests when the library processes string operations that involve dynamic memory allocation, particularly in scenarios where error conditions or exceptional flow paths do not trigger proper memory deallocation routines. Such memory leaks accumulate over time and can eventually exhaust available system resources, leading to program instability and potential system crashes.
The technical root cause of this vulnerability aligns with CWE-401, which specifically addresses improper handling of memory allocation and deallocation in software systems. The flaw occurs during the execution of string manipulation functions within the cstring library where memory is allocated for temporary string buffers or result storage but fails to be freed when the function completes or when error conditions are encountered. This improper memory management pattern creates a persistent resource drain that can be exploited by attackers to perform resource exhaustion attacks. The vulnerability is particularly concerning because it affects the fundamental string handling operations that are ubiquitous in C-based applications, making it a widespread potential security risk.
From an operational perspective, the impact of this memory leak vulnerability extends beyond simple program crashes to encompass broader system stability and availability concerns. When applications utilizing the affected cstring library experience memory leaks, they gradually consume increasing amounts of system memory, potentially leading to system slowdowns, application hangs, or complete system crashes. The vulnerability can be triggered through normal string processing operations, making it difficult to detect and prevent in production environments. Attackers could potentially exploit this vulnerability by crafting specific inputs that force the library to allocate memory repeatedly without proper cleanup, thereby accelerating the memory consumption process and increasing the likelihood of system compromise.
Mitigation strategies for CVE-2018-11097 should focus on immediate library updates and code review processes to identify and address similar memory management issues in other components. Organizations should implement comprehensive memory leak detection tools and regular code audits to identify potential vulnerabilities before they can be exploited. The ATT&CK framework categorizes this type of vulnerability under T1070.004, which addresses "Indicator Removal on Host: File Deletion," as memory leaks can be used to obscure other malicious activities by consuming system resources and creating false negatives during security monitoring. Additionally, implementing proper input validation and limiting the scope of string operations can reduce the exposure to this vulnerability, while regular system monitoring and memory usage tracking can help detect anomalous behavior indicative of memory leak exploitation attempts.