CVE-2020-0221 in Android
Summary
by MITRE
Airbrush FW's scratch memory allocator is susceptible to numeric overflow. When the overflow occurs, the next allocation could potentially return a pointer within the previous allocation's memory, which could lead to improper memory access.Product: AndroidVersions: Android kernelAndroid ID: A-135772851
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Analysis
by VulDB Data Team • 05/15/2020
The vulnerability identified as CVE-2020-0221 resides within the Airbrush firmware's scratch memory allocator implementation, representing a critical memory safety issue that can be exploited to compromise system integrity. This flaw specifically affects the Android kernel environment and is catalogued under Android ID A-135772851, highlighting its significance within the mobile operating system ecosystem. The vulnerability stems from improper handling of numeric values during memory allocation operations, creating a scenario where arithmetic overflow conditions can occur during the allocation process.
The technical flaw manifests when the memory allocator encounters numeric overflow conditions during the calculation of memory block sizes or offsets. This overflow can cause subsequent memory allocation requests to return pointers that overlap with previously allocated memory regions, creating a memory corruption scenario. When the system attempts to access memory through these overlapping pointers, it can result in improper memory access patterns that may lead to arbitrary code execution or system instability. The vulnerability is particularly concerning because it operates at the kernel level where memory management is critical for system security and stability.
From an operational impact perspective, this vulnerability presents a significant risk to Android devices running affected firmware versions. Attackers could potentially exploit this memory overflow to execute malicious code with kernel-level privileges, bypassing standard security boundaries. The attack vector typically involves crafting specific allocation requests that trigger the numeric overflow condition, followed by subsequent allocations that utilize the corrupted pointer values. This could enable privilege escalation attacks, data corruption, or complete system compromise depending on the exploitation method employed. The vulnerability's impact extends beyond individual device security to potentially affect entire device fleets if the firmware is widely deployed.
Mitigation strategies for CVE-2020-0221 should focus on implementing proper bounds checking and overflow detection within the memory allocator's numeric calculations. System administrators should ensure that affected devices receive timely firmware updates from manufacturers to address the memory allocation implementation. Additionally, runtime protections such as stack canaries, address space layout randomization, and memory integrity checks can provide additional defense-in-depth measures. Organizations should also consider monitoring for anomalous memory allocation patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-190, which covers integer overflow and wraparound conditions, and may map to ATT&CK techniques involving privilege escalation and memory corruption exploitation. The fix typically involves strengthening the memory allocator's input validation and ensuring that all arithmetic operations are properly bounded to prevent overflow conditions that could lead to pointer corruption.