CVE-2018-3561 in Android
Summary
by MITRE
In Android for MSM, Firefox OS for MSM, QRD Android, with all Android releases from CAF using the Linux kernel, a race condition in diag_ioctl_lsm_deinit() leads to a Use After Free condition.
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Analysis
by VulDB Data Team • 01/14/2020
The vulnerability identified as CVE-2018-3561 represents a critical race condition flaw within the Linux kernel implementation of Android devices manufactured by Qualcomm. This issue specifically affects Android for MSM, Firefox OS for MSM, and QRD Android platforms, creating a persistent security weakness across multiple operating systems that rely on Qualcomm's kernel modifications. The vulnerability stems from improper synchronization mechanisms within the diagnostic subsystem, particularly in the diag_ioctl_lsm_deinit() function which handles the deinitialization of local security modules.
The technical root cause of this vulnerability lies in a race condition that occurs during the dynamic deinitialization process of diagnostic kernel modules. When multiple threads or processes attempt to access or modify the same memory resources simultaneously, the system fails to properly coordinate these operations. This race condition creates a window where memory allocated to the diagnostic subsystem can be freed while still being referenced by other processes, resulting in a use-after-free condition. The flaw manifests when the diag_ioctl_lsm_deinit() function does not adequately protect against concurrent access patterns that could lead to memory corruption.
The operational impact of this vulnerability extends beyond simple memory corruption, presenting significant risks to system integrity and potential exploitation by malicious actors. An attacker who successfully exploits this condition could potentially execute arbitrary code with kernel privileges, effectively bypassing system security controls and gaining full control over the affected device. The vulnerability's presence in multiple Qualcomm-based platforms means that a wide range of mobile devices could be susceptible to exploitation, including smartphones, tablets, and other embedded systems that utilize Qualcomm's MSM processors. This creates a substantial attack surface that could enable persistent threats targeting mobile device security.
Mitigation strategies for CVE-2018-3561 require immediate patching of affected kernel versions and implementation of proper synchronization mechanisms within the diagnostic subsystem. Organizations should prioritize updating their Android devices to versions that include fixes for this vulnerability, particularly focusing on kernel modifications that address the race condition in diag_ioctl_lsm_deinit(). System administrators should also implement monitoring solutions to detect potential exploitation attempts and establish incident response procedures for addressing any successful attacks. The vulnerability aligns with CWE-362, which specifically addresses race conditions in concurrent programming, and could potentially map to ATT&CK technique T1068, which covers local privilege escalation through kernel vulnerabilities. Additionally, this flaw demonstrates the importance of proper memory management and synchronization protocols in kernel-level code, as highlighted in industry best practices for secure kernel development and the principles outlined in the CERT Secure Coding Standards.