CVE-2017-11075 in Android
Summary
by MITRE
In Qualcomm Android for MSM, Firefox OS for MSM, and QRD Android with all Android releases from CAF using the Linux kernel before security patch level 2018-04-05, if cmd_pkt and reg_pkt are called from different userspace threads, a use after free condition can potentially occur in wdsp_glink_write().
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Analysis
by VulDB Data Team • 01/20/2020
The vulnerability identified as CVE-2017-11075 represents a critical use-after-free condition within the Qualcomm Android and Firefox OS implementations that affects multiple device platforms through the Linux kernel. This flaw manifests specifically within the wdsp_glink_write() function when handling command packets and register packets that are invoked concurrently from separate userspace threads. The underlying issue stems from improper synchronization mechanisms that fail to prevent race conditions between thread execution paths, creating a scenario where memory allocated to packet processing structures becomes invalid before subsequent operations complete. The vulnerability impacts all Android releases from the Code Aurora Forum (CAF) that utilize the Linux kernel and remain unpatched before the security patch level of April 5, 2018, making it particularly concerning given the widespread adoption of Qualcomm's mobile platforms across numerous device manufacturers.
The technical exploitation of this vulnerability occurs through a classic race condition scenario where two distinct threads simultaneously access shared kernel memory structures without proper mutual exclusion controls. When cmd_pkt and reg_pkt functions are executed concurrently, the wdsp_glink_write() function may attempt to free memory resources while another thread simultaneously references those same memory locations, resulting in a use-after-free condition. This condition allows an attacker to potentially execute arbitrary code with kernel privileges, as the freed memory could be reallocated and manipulated to redirect execution flow. The vulnerability specifically targets the wireless data services (WDS) glink communication mechanism that facilitates data transmission between userspace applications and kernel drivers, making it particularly dangerous for mobile device security. According to CWE classification, this represents a CWE-416: Use After Free vulnerability, which is categorized under the broader category of memory safety issues that can lead to privilege escalation and system compromise.
The operational impact of CVE-2017-11075 extends beyond simple privilege escalation to encompass potential system instability and complete device compromise. An attacker exploiting this vulnerability could gain unauthorized access to sensitive kernel memory regions, potentially accessing cryptographic keys, user credentials, or other confidential data stored within the device's memory space. The attack surface is particularly wide given that the vulnerability affects multiple Qualcomm platforms including MSM (Mobile Station Modem) architectures used in smartphones, tablets, and IoT devices. The memory corruption resulting from the use-after-free condition could lead to kernel crashes, system lockups, or more sophisticated attacks where the attacker leverages the freed memory to inject malicious code into kernel space. This vulnerability aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation, as it provides a pathway for attackers to elevate their privileges from userspace to kernel mode, effectively bypassing standard security boundaries.
Mitigation strategies for CVE-2017-11075 require immediate implementation of security patches provided by Qualcomm and device manufacturers, as the vulnerability cannot be effectively addressed through configuration changes alone. The most effective remediation involves applying the security patches released by Qualcomm on April 5, 2018, which include proper synchronization mechanisms and memory management controls within the wdsp_glink_write() function. Organizations should also implement monitoring solutions to detect anomalous thread behavior in kernel space and establish comprehensive patch management procedures to ensure timely deployment of security updates. The vulnerability demonstrates the importance of proper inter-thread communication protocols and memory lifecycle management in kernel space, highlighting the need for rigorous code review processes that specifically address race condition vulnerabilities. Additionally, device manufacturers should consider implementing additional kernel hardening measures such as stack canaries, kernel address space layout randomization, and runtime memory protection mechanisms to further reduce the attack surface and mitigate potential exploitation attempts.