CVE-2003-0032 in libmcrypt
Summary
by MITRE
Memory leak in libmcrypt before 2.5.5 allows attackers to cause a denial of service (memory exhaustion) via a large number of requests to the application, which causes libmcrypt to dynamically load algorithms via libtool.
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Analysis
by VulDB Data Team • 09/29/2018
The vulnerability identified as CVE-2003-0032 represents a critical memory management flaw within the libmcrypt cryptographic library version 2.5.4 and earlier. This memory leak occurs during the dynamic loading of cryptographic algorithms through the libtool mechanism, creating a persistent resource consumption issue that can be exploited to perform denial of service attacks. The flaw specifically impacts applications that rely on libmcrypt for encryption operations and demonstrates a fundamental weakness in how the library handles memory allocation and deallocation during algorithm loading processes. The vulnerability is particularly concerning because it operates at the library level rather than the application level, meaning that any software utilizing libmcrypt could potentially be affected by this memory exhaustion condition.
The technical implementation of this vulnerability stems from improper memory handling within libmcrypt's algorithm loading mechanism. When applications make repeated requests to load cryptographic algorithms through libtool, the library fails to properly release previously allocated memory blocks, resulting in a gradual accumulation of memory usage over time. This memory leak manifests as a steady increase in memory consumption with each algorithm loading operation, ultimately leading to system resource exhaustion and application instability. The vulnerability operates under the broader category of memory leak weaknesses classified as CWE-401, which specifically addresses the failure to release memory resources after their use has completed. The flaw is particularly insidious because it can be triggered through legitimate application usage patterns, making it difficult to distinguish from normal operational behavior until the memory exhaustion becomes critical.
The operational impact of CVE-2003-0032 extends beyond simple service disruption to potentially compromise entire system stability and availability. Attackers can exploit this vulnerability by repeatedly invoking functions that trigger algorithm loading through libtool, causing the target system to consume increasing amounts of memory until system resources are exhausted. This type of denial of service attack can be particularly devastating in environments where libmcrypt is widely used, such as web applications, database systems, and cryptographic service providers that handle high volumes of requests. The vulnerability affects the availability aspect of the CIA triad by making systems unresponsive to legitimate requests due to resource exhaustion. From an ATT&CK framework perspective, this vulnerability maps to the privilege escalation and denial of service techniques, as it allows attackers to consume system resources and potentially gain indirect control over system availability through memory exhaustion attacks.
Mitigation strategies for CVE-2003-0032 primarily focus on upgrading to libmcrypt version 2.5.5 or later, where the memory leak has been addressed through proper memory management practices. System administrators should implement regular monitoring of memory usage patterns for applications that utilize libmcrypt to detect potential exploitation attempts before they cause significant disruption. Additionally, implementing resource limits and memory constraints on processes that use libmcrypt can help contain the impact of memory exhaustion attacks. The vulnerability highlights the importance of proper memory management in cryptographic libraries and underscores the need for thorough testing of memory handling mechanisms in security-critical software components. Organizations should also consider implementing intrusion detection systems that can monitor for unusual memory consumption patterns that might indicate exploitation attempts. The fix implemented in version 2.5.5 demonstrates the importance of maintaining up-to-date cryptographic libraries and the critical role that proper code review and testing play in preventing memory leak vulnerabilities that can be exploited for denial of service attacks.