CVE-2017-9676 in Android
Summary
by MITRE
In all Qualcomm products with Android releases from CAF using the Linux kernel, potential use after free scenarios and race conditions can occur when accessing global static variables without using a lock.
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Analysis
by VulDB Data Team • 01/14/2021
The vulnerability identified as CVE-2017-9676 represents a critical security flaw affecting Qualcomm products that incorporate Android operating systems through the Linux kernel framework. This issue manifests through improper synchronization mechanisms when accessing global static variables within the kernel space, creating conditions that can be exploited by malicious actors to compromise system integrity and potentially execute arbitrary code.
The technical root cause of this vulnerability stems from the absence of proper locking mechanisms when multiple threads or processes attempt to access shared global static variables simultaneously. This design flaw creates opportunities for use after free scenarios and race conditions that can be systematically exploited. When concurrent access occurs without adequate synchronization primitives such as mutexes, semaphores, or other locking mechanisms, the kernel's memory management can become corrupted, leading to unpredictable behavior and potential security breaches.
From an operational perspective, this vulnerability poses significant risks to devices running Qualcomm-powered Android systems, including smartphones, tablets, and other mobile devices that rely on the Linux kernel for core system operations. The race conditions and use after free scenarios can potentially allow attackers to manipulate kernel memory structures, escalate privileges, or cause system crashes that may lead to denial of service conditions. The impact extends beyond simple system instability as these vulnerabilities can provide pathways for more sophisticated attacks that compromise device security and user data confidentiality.
The vulnerability aligns with CWE-362, which specifically addresses 'Concurrent Execution using Shared Resource with Improper Synchronization,' and CWE-416, which covers 'Use After Free' conditions. These classifications highlight the fundamental nature of the flaw as a synchronization issue that allows improper access patterns to shared resources within the kernel space. The ATT&CK framework's T1068, 'Exploitation for Privilege Escalation,' and T1499, 'Endpoint Denial of Service,' further contextualize the potential attack vectors and operational impacts associated with this vulnerability.
Mitigation strategies for CVE-2017-9676 require comprehensive system updates and patches from device manufacturers, as Qualcomm would need to implement proper locking mechanisms around all global static variable access points. Organizations should prioritize immediate patch deployment across affected devices and implement monitoring solutions to detect potential exploitation attempts. Additionally, system administrators should consider implementing network segmentation and access controls to limit potential attack surface while awaiting official security updates. The vulnerability underscores the critical importance of proper synchronization in kernel-level programming and the necessity of thorough security testing for concurrent access scenarios in embedded systems.