CVE-2021-0343 in Android
Summary
by MITRE
In kisd, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation. Product: Android; Versions: Android-11; Patch ID: ALPS05449962.
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Analysis
by VulDB Data Team • 02/23/2021
The vulnerability identified as CVE-2021-0343 resides within the kisd component of Android systems, specifically affecting Android 11 builds. This issue represents a critical security flaw that manifests as an out-of-bounds write condition, a common class of memory corruption vulnerabilities that can severely compromise system integrity. The vulnerability stems from a missing bounds check within the kernel-level implementation, creating an opportunity for malicious code execution that could escalate privileges to system level access. The kisd component typically handles kernel-side operations related to system diagnostics or kernel information services, making it a critical pathway for potential privilege escalation attacks.
The technical nature of this vulnerability places it squarely within the CWE-129 category of "Improper Validation of Array Index," which is a fundamental weakness in input validation that allows attackers to manipulate array indices beyond their intended bounds. This particular flaw operates at the kernel level where the absence of proper bounds checking enables an attacker to write data beyond the allocated memory boundaries of the kisd component. The vulnerability requires system execution privileges for exploitation, indicating that it operates at a privileged level where the attacker already possesses some form of system access, though the ultimate goal remains achieving full system compromise.
The operational impact of CVE-2021-0343 extends beyond simple privilege escalation as it represents a potential pathway for attackers to gain complete control over affected Android devices. The fact that no user interaction is required for exploitation makes this vulnerability particularly dangerous as it can be triggered automatically without any user involvement. This characteristic aligns with ATT&CK technique T1068, which describes 'Local Privilege Escalation' through kernel exploits, where attackers leverage system-level vulnerabilities to elevate their access rights. The vulnerability's presence in Android 11 systems means that a significant portion of devices could be at risk, especially those that have not received the patch ALPS05449962.
The patch ID ALPS05449962 represents the specific fix implemented by the vendor to address this vulnerability, though the lack of detailed patch information in the original description limits understanding of the exact mitigation approach. This type of vulnerability typically requires memory bounds checking implementations, such as the use of size validation before array access operations, or the implementation of memory protection mechanisms that prevent unauthorized memory writes. The vulnerability's kernel-level nature also suggests that the fix likely involved implementing proper bounds validation within the kisd subsystem, potentially through the addition of checks that verify array indices against allocated memory boundaries. Organizations should ensure that all affected Android 11 devices receive the patch update immediately, as the vulnerability creates a direct pathway for attackers to achieve system-level compromise without requiring user interaction.