CVE-2021-1042 in Android
Summary
by MITRE • 12/15/2021
In dsi_panel_debugfs_read_cmdset of dsi_panel.c, there is a possible disclosure of freed kernel heap memory due to a use after free. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-187851056References: N/A
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Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-1042 represents a critical use after free condition within the Android kernel's display subsystem, specifically in the dsi_panel_debugfs_read_cmdset function located in dsi_panel.c. This flaw occurs when the kernel attempts to access memory that has already been freed during the execution of debug filesystem operations related to display panel command sets. The issue stems from improper memory management practices where the system fails to properly validate memory references before accessing them, creating a scenario where freed kernel heap memory can be read and potentially exposed to unauthorized processes.
The technical nature of this vulnerability aligns with CWE-416, which specifically addresses use after free conditions in memory management. This type of vulnerability typically arises when developers allocate memory for a data structure, use that memory for operations, and then free it, but subsequently attempt to access the freed memory location without proper validation. In the context of kernel space operations, this creates a dangerous condition where malicious actors can potentially exploit the freed memory to extract sensitive information or gain further system access. The vulnerability is particularly concerning because it operates within the kernel space, where the attacker would need system execution privileges to exploit it, but the information disclosure aspect could potentially be leveraged to gather system information that might aid in more sophisticated attacks.
From an operational impact perspective, this vulnerability enables local information disclosure, meaning that an attacker with access to a system running the affected Android kernel version could potentially extract sensitive kernel memory contents. The attack vector requires system execution privileges but does not necessitate user interaction, making it particularly dangerous in environments where local access is possible. The exposure of freed kernel heap memory could reveal sensitive data such as kernel pointers, system configuration information, or other confidential data structures that could be used for privilege escalation or further exploitation. This vulnerability directly impacts the integrity and confidentiality of the Android kernel's memory management system, potentially compromising the security boundaries that protect the operating system from unauthorized access.
The mitigation strategies for CVE-2021-1042 should focus on implementing proper memory validation before access operations and ensuring that all memory references are properly tracked throughout the execution lifecycle. System administrators should prioritize applying the relevant security patches provided by the Android security team and kernel maintainers to address this use after free condition. Additionally, the implementation of memory safety checks, including bounds checking and reference validation, should be enhanced within the kernel's display subsystem. Organizations should also consider monitoring for unusual memory access patterns that might indicate exploitation attempts and maintain up-to-date threat intelligence regarding similar vulnerabilities in the Android kernel ecosystem. The vulnerability's classification under ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation', indicates that while direct exploitation requires system privileges, the information disclosure aspect could serve as a foundation for more advanced attack vectors.