CVE-2018-10902 in Linux
Summary
by MITRE
It was found that the raw midi kernel driver does not protect against concurrent access which leads to a double realloc (double free) in snd_rawmidi_input_params() and snd_rawmidi_output_status() which are part of snd_rawmidi_ioctl() handler in rawmidi.c file. A malicious local attacker could possibly use this for privilege escalation.
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Analysis
by VulDB Data Team • 05/04/2023
The vulnerability identified as CVE-2018-10902 resides within the Linux kernel's raw midi driver implementation, specifically affecting the snd_rawmidi subsystem that handles raw midi data processing. This issue manifests as a concurrency flaw in the kernel's midi handling mechanism where proper synchronization mechanisms are absent during critical operations involving midi input and output parameter management. The vulnerability is particularly concerning because it exists at the kernel level within the rawmidi.c source file, making it a direct target for privilege escalation attacks that could compromise the entire system's security posture.
The technical flaw stems from insufficient protection against concurrent access patterns within the snd_rawmidi_input_params() and snd_rawmidi_output_status() functions that are invoked through the snd_rawmidi_ioctl() handler. When multiple threads or processes attempt to access the same midi device simultaneously, the kernel's memory management routines fail to prevent duplicate memory allocation and deallocation sequences. This double realloc scenario occurs when the same memory block is freed twice, leading to potential memory corruption that can be exploited by malicious actors to execute arbitrary code with elevated privileges. The underlying issue aligns with CWE-119 which addresses improper access to memory buffers and CWE-415 which covers double free conditions in memory management.
The operational impact of this vulnerability extends beyond simple system instability, as it provides a potential pathway for local attackers to escalate their privileges from standard user level to root access. Attackers can leverage this flaw by carefully crafting concurrent midi access patterns that trigger the double free condition during kernel execution, potentially allowing them to manipulate kernel memory structures and execute malicious code with kernel-level privileges. This makes the vulnerability particularly dangerous in multi-user environments or systems where local users might have access to midi devices or applications that interact with the raw midi subsystem. The attack vector is classified under the MITRE ATT&CK framework as privilege escalation through kernel exploits, specifically targeting the "Exploitation for Privilege Escalation" technique category.
Mitigation strategies for CVE-2018-10902 require immediate system updates and patches from the kernel maintainers to address the concurrency issues in the raw midi driver implementation. System administrators should ensure all Linux distributions are updated to versions containing the fix for this vulnerability, which typically involves implementing proper mutex or spinlock mechanisms to prevent concurrent access to the affected functions. Additionally, organizations should consider implementing runtime monitoring solutions that can detect anomalous midi device access patterns and restrict access to midi devices for non-essential applications. The vulnerability highlights the importance of proper kernel memory management and concurrent access controls, emphasizing that kernel-level drivers must implement robust synchronization mechanisms to prevent such critical flaws from being exploited by malicious actors.