CVE-2021-0657 in MT6873
Summary
by MITRE • 11/18/2021
In apusys, there is a possible out of bounds write due to a stack-based buffer overflow. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS05672103; Issue ID: ALPS05672103.
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Analysis
by VulDB Data Team • 11/22/2021
The vulnerability identified as CVE-2021-0657 resides within the apusys component of an Android-based system, representing a critical stack-based buffer overflow condition that manifests as an out-of-bounds write operation. This flaw occurs within the system's memory management mechanisms where insufficient bounds checking allows malicious data to overwrite adjacent memory locations on the stack. The vulnerability is particularly concerning as it enables local privilege escalation, potentially allowing an attacker with system execution privileges to elevate their access level to the highest system privileges available. The issue stems from improper validation of input data sizes before copying them into fixed-size stack buffers, creating an exploitable condition where attacker-controlled data can overwrite critical stack memory regions including return addresses and other control data.
The technical exploitation of this vulnerability follows a well-established pattern within the realm of stack-based buffer overflow attacks, aligning with common attack techniques documented in the attack mitigation frameworks. The flaw operates under the weakness classification of CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking permits writes beyond the allocated buffer boundaries. This vulnerability type is particularly dangerous because it can be leveraged to overwrite the return address of the calling function, effectively allowing an attacker to redirect program execution flow to arbitrary code locations. The attack vector requires no user interaction, making it particularly stealthy and dangerous as it can be exploited automatically without requiring any user engagement or social engineering tactics. The patch ID ALPS05672103 indicates that this vulnerability was addressed through a specific system update mechanism that likely involved implementing proper bounds checking and buffer size validation procedures.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data integrity violations. When successfully exploited, the vulnerability could allow an attacker to execute arbitrary code with system-level privileges, potentially leading to complete system compromise, data exfiltration, or persistent backdoor installation. The lack of user interaction requirements means that this vulnerability can be exploited in automated attacks, making it particularly dangerous in environments where system integrity is paramount. Security professionals should consider this vulnerability as a high-priority concern within their risk assessment frameworks, particularly in systems where the apusys component is actively utilized. The vulnerability's classification as a local privilege escalation issue places it within the ATT&CK framework under the privilege escalation tactic, specifically targeting the system execution privileges needed for exploitation. Organizations must implement immediate patch management procedures to address this vulnerability, as the potential for system compromise increases significantly when such vulnerabilities remain unpatched. The exploitation of this vulnerability demonstrates the critical importance of proper input validation and memory safety practices in system-level software components.