CVE-2019-19046 in Linux
Summary
by MITRE
A memory leak in the __ipmi_bmc_register() function in drivers/char/ipmi/ipmi_msghandler.c in the Linux kernel through 5.3.11 allows attackers to cause a denial of service (memory consumption) by triggering ida_simple_get() failure, aka CID-4aa7afb0ee20.
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Analysis
by VulDB Data Team • 10/14/2024
The vulnerability identified as CVE-2019-19046 represents a critical memory management flaw within the Linux kernel's IPMI (Intelligent Platform Management Interface) subsystem. This issue resides in the __ipmi_bmc_register() function located in drivers/char/ipmi/ipmi_msghandler.c, affecting all kernel versions through 5.3.11. The flaw manifests as a memory leak that occurs when the ida_simple_get() function fails during the registration process of IPMI Baseboard Management Controllers. The memory leak directly stems from improper resource cleanup when the kernel attempts to allocate identifiers for BMC registration, creating a persistent memory consumption issue that can be exploited by malicious actors.
The technical implementation of this vulnerability involves the failure of the ida_simple_get() function call within the IPMI message handler module. When this allocation function fails, the kernel does not properly release previously allocated memory resources, leading to progressive memory consumption over time. The issue is particularly concerning because it operates at the kernel level where memory management is critical for system stability and performance. The flaw follows a classic memory leak pattern where allocated resources are not properly deallocated, creating a gradual degradation of system resources that can ultimately result in system instability or complete denial of service conditions.
From an operational impact perspective, this vulnerability enables attackers to perform sustained denial of service attacks against systems running affected Linux kernel versions. The memory consumption grows progressively with each failed registration attempt, potentially exhausting available system memory and causing the system to become unresponsive or crash. The attack vector requires minimal privileges and can be executed through normal IPMI communication channels, making it particularly dangerous in enterprise environments where IPMI interfaces are commonly exposed. The vulnerability affects systems that utilize IPMI for remote management, including servers, network equipment, and other hardware components that rely on IPMI for monitoring and control functions.
The root cause of this vulnerability aligns with CWE-401, which categorizes memory leaks as a fundamental issue in resource management. The flaw demonstrates poor error handling practices where the kernel fails to implement proper cleanup routines when allocation operations fail. This vulnerability also maps to ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion. The memory leak creates a persistent condition that can be exploited by attackers to systematically consume system resources, ultimately leading to service disruption. Mitigation strategies should focus on immediate kernel updates to versions that contain the patched implementation of the ipmi_msghandler.c module. Additionally, system administrators should implement monitoring for unusual memory consumption patterns and consider disabling IPMI interfaces when not actively required, particularly in environments where the attack surface needs to be minimized.
The vulnerability highlights the importance of robust error handling in kernel space operations, where resource management failures can have cascading effects on system stability. The implementation of proper resource cleanup routines, particularly in functions that handle dynamic allocation failures, is essential for preventing such memory leaks. Organizations should prioritize patch management for kernel components and maintain awareness of similar vulnerabilities in other kernel subsystems that may exhibit similar resource management issues. The long-term impact of this vulnerability underscores the need for comprehensive security testing of kernel modules, particularly those handling hardware interfaces and resource allocation operations that are critical to system operation and availability.