CVE-2021-0664 in MT6765
Summary
by MITRE • 11/18/2021
In ccu, there is a possible memory corruption due to a use after free. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS05827158; Issue ID: ALPS05827158.
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Analysis
by VulDB Data Team • 11/22/2021
The vulnerability identified as CVE-2021-0664 affects the ccu component within Android systems, representing a critical memory corruption issue that stems from a use after free condition. This flaw resides in the kernel-level subsystem responsible for managing device communication and control operations, making it particularly dangerous as it operates with elevated privileges. The vulnerability manifests when the system attempts to access memory that has already been freed, creating opportunities for arbitrary code execution and privilege escalation. The use after free condition occurs when the ccu module fails to properly manage memory references, allowing attackers to manipulate freed memory locations and potentially overwrite critical system data structures. This memory management error falls under CWE-416, which specifically addresses use after free vulnerabilities that can lead to severe security implications. The vulnerability requires system execution privileges for exploitation, indicating that the attacker must already have some level of access to the device before leveraging this flaw to escalate privileges further.
The operational impact of CVE-2021-0664 extends beyond simple privilege escalation as it represents a local attack vector that can be exploited without user interaction, making it particularly concerning for mobile device security. When successfully exploited, this vulnerability can enable attackers to gain full system privileges, potentially allowing them to access sensitive device data, modify system configurations, or install malicious software. The attack surface is particularly wide given that the ccu component typically handles critical device communication protocols and may be accessed by multiple system processes. The vulnerability's classification as a local privilege escalation issue means that an attacker with minimal initial access could leverage this flaw to achieve complete system compromise, which aligns with the ATT&CK technique T1068 for local privilege escalation. The fact that this vulnerability does not require user interaction makes it especially dangerous as it can be exploited automatically by malicious applications or through compromised system services, potentially affecting all users of vulnerable Android devices.
The patch addressing CVE-2021-0664, identified by patch ID ALPS05827158 and issue ID ALPS05827158, demonstrates that this vulnerability was recognized and remediated by the Android security team. The fix likely involves implementing proper memory management procedures within the ccu subsystem to prevent the use after free condition from occurring. This type of patch typically includes memory reference validation, proper deallocation procedures, and potentially additional bounds checking mechanisms to ensure that freed memory locations cannot be accessed or reused. Organizations and device manufacturers should prioritize applying this patch across all affected Android devices to prevent exploitation of this vulnerability. The remediation process requires careful consideration of the patch compatibility and potential side effects on device functionality, as memory management fixes can sometimes introduce regressions in system behavior. Security teams should monitor for any potential exploitation attempts and ensure that device firmware updates are deployed promptly to protect against this specific threat vector. The vulnerability serves as a reminder of the critical importance of proper memory management in kernel-level components and the potential consequences when such management fails in mobile operating systems.