CVE-2015-8939 in Android
Summary
by MITRE
drivers/video/msm/mdp4_util.c in the Qualcomm components in Android before 2016-08-05 on Nexus 7 (2013) devices does not validate r stages, g stages, or b stages data, which allows attackers to gain privileges via a crafted application, aka Android internal bug 28398884 and Qualcomm internal bug CR779021.
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Analysis
by VulDB Data Team • 09/12/2022
The vulnerability identified as CVE-2015-8939 resides within the Qualcomm multimedia display processor driver component of Android operating systems, specifically affecting Nexus 7 (2013) devices released before the security patch date of August 5, 2016. This flaw exists in the mdp4_util.c file which forms part of the Qualcomm components responsible for handling display processing operations. The issue represents a critical privilege escalation vulnerability that enables malicious applications to elevate their privileges from standard user-level access to system-level administrative rights, fundamentally compromising the security model of the affected Android devices.
The technical root cause of this vulnerability stems from inadequate input validation within the display processing subsystem where the driver fails to properly validate the red stages, green stages, and blue stages data parameters. These parameters control the color channel processing within the multimedia display processor and are critical for proper display functionality. The absence of proper validation mechanisms allows attackers to craft malicious applications that can manipulate these parameters in ways that bypass normal security checks. This validation failure creates a direct pathway for privilege escalation attacks, as the driver accepts malformed or unexpected data without proper sanitization or verification.
From an operational perspective, this vulnerability presents a severe threat to device security and user privacy. Attackers can exploit this weakness through seemingly benign applications that leverage the malformed data inputs to gain unauthorized system access. Once escalated, these privileges enable full control over device functions including access to sensitive user data, modification of system files, installation of malicious software, and potential network monitoring capabilities. The impact extends beyond individual device compromise to potentially enable large-scale attacks if attackers can distribute malicious applications through legitimate app stores or other distribution channels.
The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of insufficient validation of input data within kernel-level drivers. From an attacker's methodology standpoint, this flaw maps to multiple ATT&CK techniques including privilege escalation through kernel exploits and persistence mechanisms that can maintain access even after device reboots. The exploitation process typically involves crafting a malicious application that loads the vulnerable driver component and sends specially crafted parameters to trigger the privilege escalation. The vulnerability also demonstrates characteristics of attack vectors related to driver-based attacks and kernel exploits that have been documented in various security research publications and threat intelligence reports.
Organizations and users should immediately implement the security patches released by Google and Qualcomm to address this vulnerability. The recommended mitigation strategy includes applying the August 2016 security updates for Android devices, particularly targeting the Nexus 7 (2013) models that were affected by this issue. System administrators should also consider implementing additional security controls such as application whitelisting, regular security assessments of device configurations, and monitoring for suspicious application behavior that might indicate exploitation attempts. The vulnerability underscores the importance of maintaining current security patches and highlights the critical need for proper input validation in kernel-level components that handle sensitive system operations.