CVE-2018-9368 in Android
Summary
by MITRE • 11/19/2024
In mtkscoaudio debugfs there is a possible arbitrary kernel memory write due to missing bounds check and weakened SELinux policies. This could lead to local escalation of privilege with system execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 11/19/2024
The vulnerability identified as CVE-2018-9368 resides within the mtkscoaudio debugfs component of certain Android kernel implementations, specifically affecting MediaTek-based devices. This issue represents a critical security flaw that stems from insufficient input validation mechanisms within the kernel's debug interface. The vulnerability manifests through the absence of proper bounds checking in the debugfs file operations, creating a pathway for malicious code to write arbitrary data to kernel memory locations. The weakness is compounded by weakened SELinux policies that fail to adequately restrict access to these sensitive kernel interfaces, effectively removing critical mandatory access controls that should prevent unauthorized memory manipulation.
The technical exploitation of this vulnerability occurs through the manipulation of debugfs file operations within the mtkscoaudio driver. When a local attacker accesses the debugfs interface without proper bounds checking, they can craft malicious input that overflows kernel buffers or writes data to arbitrary memory addresses. This lack of input validation creates a classic buffer overflow condition that can be leveraged to overwrite kernel memory structures, potentially leading to privilege escalation. The vulnerability's classification as a local privilege escalation issue means that an attacker must already have user-level access to the device but can leverage this flaw to gain system-level execution privileges. The absence of user interaction requirements makes this vulnerability particularly dangerous as it can be exploited automatically without requiring any form of social engineering or user deception.
The operational impact of CVE-2018-9368 extends beyond simple privilege escalation, as it can enable attackers to achieve complete system compromise. Successful exploitation allows malicious actors to execute arbitrary code with kernel-level privileges, potentially leading to full device takeover, data exfiltration, or persistent backdoor installation. The weakened SELinux policies exacerbate the threat landscape by removing crucial access controls that would normally prevent unauthorized memory manipulation. This vulnerability affects devices running Android versions that incorporate the affected MediaTek driver components, particularly those utilizing the mtkscoaudio audio subsystem. The attack surface is limited to specific MediaTek chipsets and kernel configurations, but the impact remains severe due to the kernel-level privileges that can be gained.
Mitigation strategies for this vulnerability focus on both immediate patching and operational security improvements. The primary solution involves applying the relevant kernel patches that implement proper bounds checking and restore appropriate SELinux policies for the debugfs interface. Organizations should prioritize updating their Android device firmware to versions that address this specific vulnerability. Additionally, implementing runtime protections such as kernel address space layout randomization kASLR and stack canaries can help mitigate exploitation attempts. Security configurations should include restoring default SELinux policies and disabling unnecessary debugfs interfaces on production devices. The vulnerability aligns with CWE-121 and CWE-122 categories related to buffer overflow conditions and improper input validation, while its exploitation techniques correspond to ATT&CK tactics including privilege escalation and defense evasion through kernel manipulation. Regular security audits of kernel interfaces and access controls remain essential for identifying similar vulnerabilities in other driver components that may present analogous security risks.