CVE-2023-35685 in Android
Summary
by MITRE • 01/08/2025
In DevmemIntMapPages of devicemem_server.c, there is a possible physical page uaf due to a logic error in the code. This could lead to local escalation of privilege in the kernel with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 02/01/2025
The vulnerability identified as CVE-2023-35685 resides within the kernel-level device memory mapping functionality of a specific system component. This flaw manifests in the DevmemIntMapPages function located in the devicemem_server.c source file, representing a critical security weakness that affects the integrity of kernel memory management operations. The vulnerability classifies as a use-after-free condition that occurs during physical page handling, where improper memory lifecycle management creates opportunities for malicious exploitation.
The technical root cause stems from a logic error within the kernel's device memory mapping implementation that fails to properly validate or manage reference counts for physical memory pages during mapping operations. When the system attempts to map device memory pages, the code path containing DevmemIntMapPages does not adequately handle the scenario where a page reference might be freed while still being accessible to other code paths. This logical flaw creates a window where freed memory can be reallocated and accessed, leading to potential memory corruption and arbitrary code execution capabilities. The vulnerability operates at the kernel level, meaning that successful exploitation can result in complete system compromise without requiring any elevated privileges or user interaction.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system stability and data integrity threats. An attacker who successfully exploits this use-after-free condition could execute arbitrary code with kernel-level privileges, effectively bypassing all user-space security controls and gaining complete control over the target system. The lack of user interaction requirement makes this vulnerability particularly dangerous as it can be exploited automatically without any human intervention. This type of vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in memory management, and represents a classic example of how improper reference counting can lead to privilege escalation attacks. The ATT&CK framework categorizes this as a privilege escalation technique where adversaries leverage kernel-level vulnerabilities to gain elevated system access.
Mitigation strategies for CVE-2023-35685 require immediate patching of affected systems, as the vulnerability exists within the kernel itself and cannot be addressed through user-space solutions alone. System administrators should prioritize deployment of vendor-provided security patches that correct the logic error in the DevmemIntMapPages function and properly manage physical page reference counts. Additionally, implementing kernel memory protection mechanisms such as kernel page table isolation and enabling security features like stack canaries can provide additional defense-in-depth layers. Regular security audits of kernel code should include thorough review of memory management functions to identify similar logic flaws, while monitoring systems should be configured to detect anomalous kernel memory access patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper memory lifecycle management in kernel space and serves as a reminder that even seemingly simple memory operations can have catastrophic security implications when logic errors are present.