CVE-2018-13893 in Android
Summary
by MITRE
In all android releases(Android for MSM, Firefox OS for MSM, QRD Android) from CAF using the linux kernel, Out of bound mask range access caused by using possible old value of msg mask table count while copying masks to userspace.
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Analysis
by VulDB Data Team • 05/09/2020
This vulnerability exists in Android operating systems running on Qualcomm MSM platforms including various Android for MSM, Firefox OS for MSM, and QRD Android variants. The issue stems from improper handling of message mask table counts during kernel operations, specifically when copying mask data to userspace. The root cause lies in the kernel's failure to properly validate or update the message mask table count before performing memory operations, leading to potential out-of-bounds memory access scenarios.
The technical flaw manifests when the kernel attempts to copy message masks to userspace using what may be an outdated or stale value of the message mask table count. This condition creates a scenario where the kernel calculates memory boundaries based on a previous state of the mask table, potentially allowing access beyond the allocated memory regions. Such out-of-bounds access can result in memory corruption, data leakage, or potentially exploitable conditions that could allow privilege escalation or denial of service attacks.
The operational impact of this vulnerability extends across multiple Android variants and Qualcomm-based devices, affecting a broad range of mobile platforms. Attackers could potentially exploit this condition to execute arbitrary code with kernel-level privileges, undermining the security model of the Android operating system. The vulnerability represents a classic buffer over-read issue that could be leveraged for privilege escalation, information disclosure, or system stability compromise. Given that this affects kernel-level operations, successful exploitation could result in complete system compromise and persistent access to device resources.
Mitigation strategies should focus on updating to patched kernel versions from Qualcomm and device manufacturers, implementing proper input validation for message mask table counts, and ensuring that kernel memory operations always use current values rather than potentially stale data. Organizations should also consider implementing runtime monitoring for suspicious memory access patterns and ensure that all Android devices receive timely security updates. This vulnerability aligns with CWE-129 and CWE-787 categories related to improper input validation and out-of-bounds read conditions, and could be categorized under ATT&CK techniques involving privilege escalation and kernel exploitation. The issue demonstrates the critical importance of proper state management in kernel code and the potential for seemingly minor validation gaps to create significant security risks in mobile operating systems.