CVE-2015-9000 in Android
Summary
by MITRE
In TrustZone an untrusted pointer dereference vulnerability can potentially occur in a DRM routine in all Android releases from CAF using the Linux kernel.
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Analysis
by VulDB Data Team • 12/24/2020
The vulnerability identified as CVE-2015-9000 represents a critical security flaw within the TrustZone secure execution environment of Android devices that utilize Qualcomm Chipsets and the Linux kernel. This issue manifests as an untrusted pointer dereference in a Digital Rights Management routine, creating a potential attack vector that could compromise the integrity of the secure subsystem. The vulnerability affects all Android releases that incorporate Qualcomm's Android Common Platform (CAF) and utilize the Linux kernel, making it widespread across numerous device models and manufacturers. The TrustZone technology, designed to provide a secure environment for sensitive operations including DRM processing, becomes compromised when this vulnerability is exploited, potentially allowing malicious actors to bypass security measures and access protected content or system resources. The flaw specifically resides in how the DRM routine handles pointer validation, creating a scenario where untrusted input can lead to arbitrary code execution or system instability.
This vulnerability directly maps to CWE-476 which defines the weakness of null pointer dereference, and more specifically relates to the broader category of pointer-related vulnerabilities that can be exploited in secure execution environments. The technical implementation flaw occurs within the kernel-level DRM processing code where input validation is insufficient, allowing an attacker to manipulate pointers through malicious input or crafted payloads. The exploitation requires an attacker to have access to the system through a lower privileged execution context, as the vulnerability exists in a routine that processes DRM content. The lack of proper bounds checking and pointer validation in the TrustZone component means that when untrusted data is processed through the DRM routine, it can lead to memory corruption that may result in privilege escalation or complete system compromise. The vulnerability's impact is particularly severe because TrustZone is designed to be a trusted execution environment, and its compromise undermines the fundamental security model of the device.
The operational impact of CVE-2015-9000 extends beyond simple system instability, as it represents a complete breakdown of the secure execution environment's integrity. Attackers can potentially exploit this vulnerability to gain unauthorized access to protected content, bypass digital rights management protections, and access sensitive data that should only be available within the secure TrustZone environment. The vulnerability also creates opportunities for privilege escalation attacks where an attacker could leverage the compromised DRM routine to gain elevated system privileges. Additionally, the flaw could enable attackers to inject malicious code into the secure execution environment, potentially allowing them to modify or corrupt system firmware, or even create persistent backdoors that survive system reboots. The widespread nature of this vulnerability means that numerous Android devices across different manufacturers and model lines are potentially at risk, creating a significant security concern for both individual users and enterprise environments that rely on device security.
Mitigation strategies for CVE-2015-9000 require immediate patching of affected Android versions through security updates from device manufacturers and carriers. Organizations should implement monitoring systems to detect potential exploitation attempts and ensure that all devices are running the latest security patches from their respective vendors. The vulnerability can be addressed through kernel-level modifications that enforce proper pointer validation and input sanitization within the DRM routines. System administrators should also consider implementing additional security controls such as runtime application protection and memory protection mechanisms to limit the impact of potential exploitation attempts. The implementation of these mitigations should align with industry standards such as those defined in the NIST Cybersecurity Framework and should be consistent with the principles outlined in the MITRE ATT&CK framework for mobile threats. Device manufacturers should also conduct thorough security testing of all kernel components, particularly those related to secure execution environments and DRM processing, to prevent similar vulnerabilities from being introduced in future releases. Regular security assessments and vulnerability scanning should be implemented as part of the device lifecycle management to identify and remediate potential security flaws before they can be exploited by malicious actors.