CVE-2021-0495 in Android
Summary
by MITRE • 06/11/2021
In memory management driver, there is a possible out of bounds write due to uninitialized data. 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-183459083
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Analysis
by VulDB Data Team • 06/18/2021
The vulnerability identified as CVE-2021-0495 resides within the memory management driver component of Android operating systems, specifically affecting Android SoC implementations. This flaw represents a critical security weakness that could potentially be exploited by malicious actors to achieve local privilege escalation without requiring additional execution privileges or user interaction. The vulnerability manifests as an out of bounds write condition that occurs due to the presence of uninitialized data within the memory management subsystem, creating a pathway for unauthorized system access and control.
The technical root cause of this vulnerability stems from improper initialization of memory variables within the driver code, which creates a scenario where data can be written beyond the allocated memory boundaries. According to CWE classification, this vulnerability aligns with CWE-457: Use of uninitialized variable, which is a fundamental programming error that occurs when a program attempts to use a variable before it has been properly initialized. The memory management driver's failure to initialize critical data structures before processing memory operations creates an exploitable condition where attacker-controlled data can overwrite adjacent memory locations, potentially corrupting system-critical data structures or executing arbitrary code with elevated privileges.
From an operational perspective, this vulnerability presents a significant risk to Android devices since it enables local privilege escalation without requiring any additional attack vectors or user interaction. The exploitation process leverages the uninitialized data condition to manipulate memory layout and execute code with higher privileges than initially granted to the user or application. This represents a direct violation of the principle of least privilege and could allow an attacker to gain root access to the device, potentially leading to complete system compromise, data theft, or persistent backdoor installation. The lack of user interaction requirement makes this vulnerability particularly dangerous as it can be exploited automatically upon device boot or during normal operation.
The security implications extend beyond simple privilege escalation as this vulnerability could enable attackers to bypass Android's security model entirely, including SELinux policies, application sandboxing, and other runtime protections. Attackers could leverage this vulnerability to modify system binaries, install malicious applications with system-level privileges, or establish persistent access to the device. The vulnerability's impact is amplified by its location within the memory management driver, which operates at a low system level and has direct access to critical memory resources. Organizations and users should consider this vulnerability as a high-priority threat requiring immediate attention and remediation.
Mitigation strategies should focus on both immediate patching and defensive measures to protect against exploitation of this vulnerability. Android security patches addressing this issue should be applied immediately to all affected devices, with particular attention to Android SoC implementations that are vulnerable to this memory management flaw. System administrators should implement additional monitoring and logging of memory management operations to detect potential exploitation attempts. The vulnerability's characteristics align with ATT&CK technique T1068: Exploitation for Privilege Escalation, making it a prime target for attackers seeking to establish persistent access and execute malicious activities with elevated privileges. Organizations should also consider implementing memory protection mechanisms such as stack canaries and address space layout randomization to reduce the exploitability of similar uninitialized variable vulnerabilities.