CVE-2017-8277 in Android
Summary
by MITRE
In all Qualcomm products with Android releases from CAF using the Linux kernel, in the function msm_dba_register_client, if the client registers failed, it would be freed. However the client was not removed from list. Use-after-free would occur when traversing the list next time.
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Analysis
by VulDB Data Team • 01/14/2021
The vulnerability identified as CVE-2017-8277 represents a critical use-after-free flaw in Qualcomm's Android implementations that leverages the Linux kernel. This issue affects all Qualcomm products utilizing Android releases from the Code Aurora Forum that incorporate the Linux kernel. The vulnerability manifests within the msm_dba_register_client function, which handles client registration processes for the Qualcomm Data Bus Architecture. When a client registration fails during the registration process, the system properly frees the client structure from memory but fails to remove the corresponding entry from the linked list data structure that maintains active client references. This fundamental oversight creates a persistent dangling pointer that remains accessible within the list structure even after the memory has been deallocated.
The technical exploitation of this vulnerability occurs through the traversal of the client list data structure during subsequent operations. When the system attempts to iterate through the list of registered clients, it encounters the freed client entry that still exists within the list structure, leading to a use-after-free condition. This condition allows an attacker to potentially manipulate the freed memory location, causing unpredictable behavior that could result in arbitrary code execution or system instability. The flaw resides in the fundamental memory management practices within the kernel module, specifically in the client registration and cleanup routines that fail to maintain proper list integrity. This type of vulnerability falls under CWE-416, which specifically addresses the use of freed memory conditions, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution through kernel-level manipulation.
The operational impact of CVE-2017-8277 extends beyond simple system crashes, as it creates potential attack vectors for privilege escalation and persistent system compromise. Attackers who can trigger the specific conditions leading to client registration failure and subsequent list traversal can potentially leverage this vulnerability to execute malicious code with kernel-level privileges. The vulnerability affects a broad range of Qualcomm-based devices including smartphones, tablets, and other mobile platforms that utilize the Linux kernel with Qualcomm's Data Bus Architecture implementation. This creates a significant risk across multiple device categories and makes the vulnerability particularly dangerous from a security perspective. The exploitation requires precise timing and specific conditions related to client registration failures, but once achieved, provides a stable foundation for advanced persistent threats. The vulnerability's impact is further amplified by the fact that it affects the core kernel infrastructure that manages data communication between various system components, making it a prime target for sophisticated attack campaigns. Mitigation efforts must focus on proper list management during error conditions, ensuring that all references to freed memory are properly removed from data structures, and implementing robust memory management practices that prevent dangling pointer scenarios.