CVE-2015-9111 in Android
Summary
by MITRE
In Android before 2018-04-05 or earlier security patch level on Qualcomm Snapdragon Automobile and Snapdragon Mobile MDM9625, SD 425, SD 430, SD 450, SD 625, SD 650/52, SD 820, and SD 820A, in a QTEE syscall handler, an untrusted pointer dereference can occur.
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Analysis
by VulDB Data Team • 01/26/2020
The vulnerability identified as CVE-2015-9111 represents a critical security flaw affecting Android devices equipped with specific Qualcomm Snapdragon chipsets including the Snapdragon Automobile and various mobile SoC variants. This issue resides within the Qualcomm TrustZone Execution Environment (QTEE) syscall handler, which operates in a secure execution environment separate from the main Android operating system. The vulnerability manifests as an untrusted pointer dereference that can be exploited by malicious actors to compromise the secure execution environment. The affected chipsets span multiple generations including the MDM9625, SD 425, SD 430, SD 450, SD 625, SD 650/52, SD 820, and SD 820A processors, indicating a widespread impact across Qualcomm's automotive and mobile product lines.
The technical nature of this vulnerability stems from improper validation of pointers within the QTEE syscall handler implementation. When processing system calls from untrusted user-space applications, the handler fails to adequately verify pointer values before dereferencing them, creating a potential pathway for arbitrary code execution within the secure environment. This flaw directly maps to CWE-476 which describes NULL pointer dereference conditions, and more specifically relates to CWE-121 which covers stack-based buffer overflow conditions that can lead to pointer corruption. The vulnerability exists in the kernel-level code that manages trustzone operations, making it particularly dangerous as it operates below the normal operating system security boundaries.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it allows attackers to potentially bypass the fundamental security model of the TrustZone environment. Successful exploitation could enable malicious actors to gain elevated privileges within the secure execution environment, potentially leading to complete device compromise, data exfiltration, or persistent backdoor installation. The vulnerability affects devices that were released prior to the 2018-04-05 security patch level, meaning that automotive systems and mobile devices using these chipsets could be at risk for years after initial deployment. This long window of exposure increases the likelihood of exploitation in real-world scenarios, particularly in automotive environments where patching cycles may be extended.
Mitigation strategies for this vulnerability primarily focus on applying the appropriate security patches released by Qualcomm and device manufacturers. The affected devices should be updated to versions containing the patched QTEE syscall handler implementation that properly validates pointer inputs before dereferencing. Organizations should also consider implementing additional monitoring and detection measures to identify potential exploitation attempts within their networks. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and execution within secure environments, specifically targeting the system root level. Network administrators should implement network-based intrusion detection systems to monitor for exploitation attempts and ensure that all affected devices receive timely security updates to prevent unauthorized access to the secure execution environment.