CVE-2022-48915 in Linux
Summary
by MITRE • 08/22/2024
In the Linux kernel, the following vulnerability has been resolved:
thermal: core: Fix TZ_GET_TRIP NULL pointer dereference
Do not call get_trip_hyst() from thermal_genl_cmd_tz_get_trip() if the thermal zone does not define one.
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Analysis
by VulDB Data Team • 08/28/2024
The vulnerability CVE-2022-48915 represents a critical null pointer dereference issue within the Linux kernel's thermal management subsystem. This flaw exists in the thermal zone (TZ) core functionality where the system attempts to access memory locations that have not been properly initialized, potentially leading to system crashes or unauthorized access to kernel memory spaces. The vulnerability specifically impacts the thermal_genl_cmd_tz_get_trip() function which handles network command processing for thermal zone trip point retrieval operations. When a thermal zone object lacks trip point definitions, the function incorrectly attempts to invoke get_trip_hyst() on a null pointer, creating an exploitable condition that can be triggered through malicious network commands or system calls.
The technical implementation of this vulnerability stems from inadequate input validation within the thermal subsystem's command processing logic. According to CWE-476, this represents a null pointer dereference flaw where the thermal zone management code fails to properly check for null references before attempting function calls. The issue manifests when the thermal_genl_cmd_tz_get_trip() function processes commands without verifying whether the thermal zone object contains valid trip point definitions. This failure to validate pointer references creates a path where a null pointer is passed to get_trip_hyst(), resulting in a kernel panic or potential privilege escalation depending on the execution context. The vulnerability directly relates to improper handling of kernel data structures and lacks proper defensive programming practices that should validate all pointer references before dereferencing.
Operationally, this vulnerability poses significant risks to embedded systems, servers, and devices running Linux kernels that utilize thermal management features. Attackers could exploit this condition by sending specially crafted network commands through the generic netlink interface to trigger the null pointer dereference, potentially causing system instability or denial of service attacks. In environments where thermal management is critical for hardware protection, such as data centers, automotive systems, or industrial IoT devices, this vulnerability could lead to system crashes that compromise device functionality. The ATT&CK framework categorizes this as a privilege escalation technique through kernel exploitation, as successful exploitation could allow attackers to gain elevated privileges within the kernel space. Additionally, the vulnerability could be leveraged in persistent denial of service scenarios where repeated exploitation causes system instability and requires manual intervention to restore normal operation.
Mitigation strategies for CVE-2022-48915 focus on implementing proper null pointer validation and defensive programming practices within the thermal subsystem. System administrators should prioritize applying kernel updates that include the patched thermal core implementation, which ensures that get_trip_hyst() is only invoked when the thermal zone object contains valid trip point definitions. The fix implements a conditional check before calling the function, preventing the null pointer dereference condition. Organizations should also consider implementing kernel lockdown mechanisms and restricting network access to thermal management interfaces where possible. Monitoring for unusual thermal management command sequences and implementing intrusion detection systems can help identify potential exploitation attempts. Security teams should conduct regular kernel vulnerability assessments and ensure that all systems running affected kernel versions receive timely patches, particularly in critical infrastructure environments where system stability is paramount. The vulnerability demonstrates the importance of proper error handling in kernel space operations and reinforces the necessity of comprehensive testing for edge cases in system-level programming.