CVE-2019-19062 in Linux
Summary
by MITRE
A memory leak in the crypto_report() function in crypto/crypto_user_base.c in the Linux kernel through 5.3.11 allows attackers to cause a denial of service (memory consumption) by triggering crypto_report_alg() failures, aka CID-ffdde5932042.
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Analysis
by VulDB Data Team • 02/23/2024
The vulnerability identified as CVE-2019-19062 represents a critical memory management flaw within the Linux kernel's cryptographic subsystem that enables malicious actors to exploit a memory leak condition. This issue exists in the crypto_report() function located in the crypto/crypto_user_base.c file and affects all Linux kernel versions up to and including 5.3.11. The vulnerability specifically manifests when the crypto_report_alg() function encounters failures during cryptographic algorithm reporting operations, creating a scenario where allocated memory is not properly released back to the system. The flaw operates at the kernel level, making it particularly dangerous as it can be triggered by unprivileged users or processes that have access to the cryptographic subsystem.
The technical mechanism behind this memory leak involves improper memory deallocation within the kernel's cryptographic framework when error conditions occur during algorithm reporting. When crypto_report_alg() fails to process cryptographic algorithm information correctly, the memory allocated for reporting structures remains allocated and unreclaimed by the kernel's memory management system. This creates a gradual accumulation of unreleased memory fragments that can eventually consume significant portions of system memory resources. The vulnerability is categorized under CWE-401 as a weakness related to improper management of memory allocation and deallocation, specifically manifesting as a memory leak that can be exploited for denial of service attacks. The flaw demonstrates characteristics consistent with the ATT&CK technique T1499.004 which involves resource exhaustion through memory leaks and allocation failures.
The operational impact of this vulnerability extends beyond simple memory consumption, as it can lead to complete system instability and denial of service conditions. When attackers repeatedly trigger the memory leak condition, they can progressively consume available system memory until the kernel is forced to terminate critical processes or become unresponsive to legitimate system operations. This type of attack can be particularly devastating in server environments where continuous availability is critical, as it can effectively render systems unusable without requiring elevated privileges or sophisticated attack vectors. The vulnerability affects any system running affected kernel versions that utilize the cryptographic subsystem, making it widespread across various deployment scenarios including cloud infrastructure, enterprise servers, and embedded systems that depend on Linux kernel cryptographic services.
Mitigation strategies for this vulnerability primarily focus on kernel version updates and system hardening measures. The most effective immediate solution involves upgrading to a patched kernel version that addresses the memory leak condition in the crypto_report() function. System administrators should prioritize applying security patches from their respective distribution vendors or directly from the Linux kernel security team. Additionally, monitoring systems should be implemented to detect unusual memory consumption patterns that may indicate exploitation attempts. Network segmentation and access control measures can help limit potential attack surface by restricting access to cryptographic subsystem interfaces. The vulnerability serves as a reminder of the critical importance of proper memory management in kernel space operations and highlights the need for comprehensive security testing of core system components. Organizations should implement regular security assessments of their kernel versions and maintain up-to-date patch management procedures to prevent exploitation of similar memory management vulnerabilities.