CVE-2019-2111 in Android
Summary
by MITRE
In loop of DnsTlsSocket.cpp, there is a possible heap memory corruption due to a use after free. This could lead to remote code execution in the netd server with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android. Versions: Android-9. Android ID: A-122856181.
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Analysis
by VulDB Data Team • 07/02/2020
The vulnerability identified as CVE-2019-2111 represents a critical heap memory corruption flaw within the Android netd server implementation. This issue manifests in the DnsTlsSocket.cpp file where a loop structure contains a use after free condition that can be exploited to achieve remote code execution. The vulnerability exists specifically within Android 9.0 operating system versions and was tracked under Android ID A-122856181. The flaw stems from improper memory management practices where freed memory locations are accessed after being deallocated, creating opportunities for attackers to manipulate heap memory structures.
The technical nature of this vulnerability places it firmly within the realm of memory corruption vulnerabilities, specifically categorized under CWE-416 Use After Free, which is a well-documented weakness in software security. The exploitation occurs through the netd server process that handles network operations, making this a particularly dangerous flaw since it operates with system-level privileges. The use after free condition in the loop structure of DnsTlsSocket.cpp creates a scenario where attackers can corrupt heap memory by accessing previously freed memory locations, potentially allowing them to overwrite critical data structures or execute arbitrary code. This memory corruption can be leveraged to gain unauthorized control over the device's network operations and potentially escalate privileges.
The operational impact of CVE-2019-2111 is severe as it enables remote code execution without requiring any user interaction or additional privileges beyond what is normally available to network services. This means that an attacker could exploit this vulnerability from a remote location without needing physical access to the device or user engagement. The netd server serves as a critical network management component in Android systems, making this vulnerability particularly dangerous as it can affect DNS resolution, network configuration, and overall system network connectivity. The attack vector involves manipulating DNS over TLS connections, which are commonly used for secure network communications, making the exploitation both stealthy and effective.
Security mitigations for this vulnerability require immediate patching of affected Android 9.0 devices through official security updates from Google and device manufacturers. System administrators should prioritize deployment of these patches across all affected devices, particularly those handling sensitive network communications. The vulnerability also highlights the importance of proper memory management practices in system-level components and demonstrates the critical need for thorough code review processes focusing on heap management. Network monitoring should be enhanced to detect anomalous DNS over TLS traffic patterns that might indicate exploitation attempts, while also implementing network segmentation to limit potential lateral movement if exploitation occurs. Organizations should also consider implementing additional security controls such as application whitelisting and network access controls to reduce the attack surface and prevent unauthorized access to vulnerable network services.