CVE-2021-0696 in Android
Summary
by MITRE • 10/12/2022
In dllist_remove_node of TBD, there is a possible use after free bug due to a race condition. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android SoCAndroid ID: A-242344778
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Analysis
by VulDB Data Team • 12/31/2022
The vulnerability identified as CVE-2021-0696 resides within the dllist_remove_node function of a system component, representing a critical use after free condition that emerges from a race condition scenario. This flaw manifests in the Android operating system environment, specifically affecting Android SoC implementations where the vulnerability was tracked under Android ID A-242344778. The technical nature of this issue places it squarely within the realm of memory safety vulnerabilities, where improper handling of memory references can lead to system compromise. The presence of a race condition indicates that the vulnerability occurs when multiple threads or processes attempt to access the same memory location simultaneously, creating a window where memory deallocation and subsequent access can occur in an improper sequence.
The operational impact of this vulnerability extends to local privilege escalation capabilities, meaning that an attacker with minimal privileges could potentially elevate their access level within the system. This represents a significant security risk as it allows for unauthorized access to system resources and functionality that would normally be restricted to privileged users. The vulnerability does not require user interaction for exploitation, which makes it particularly concerning as it can be triggered automatically without any user engagement. This characteristic aligns with the ATT&CK framework's privilege escalation techniques, where automated exploitation methods are employed to gain higher system privileges. The absence of user interaction requirements means that the vulnerability could be exploited in automated attacks or during normal system operation when the race condition occurs.
From a security standards perspective, this vulnerability maps directly to CWE-416, which specifically addresses use after free conditions in software development. The race condition aspect of the flaw demonstrates poor synchronization practices in concurrent programming, where proper locking mechanisms or atomic operations should have been implemented to prevent multiple access patterns to the same memory resource. The vulnerability's classification as a local privilege escalation means it falls under the broader category of local attack vectors that can be particularly dangerous in multi-user or multi-process environments. The exploitation of such a flaw typically requires understanding of the underlying memory management mechanisms and the specific timing conditions that trigger the race condition. Mitigation strategies should focus on implementing proper synchronization primitives, memory management controls, and thorough code review processes to prevent similar race condition scenarios from occurring in future implementations. The Android platform's security model relies heavily on proper memory management and synchronization to maintain system integrity, making this type of vulnerability particularly critical to address through comprehensive patching and architectural improvements.