CVE-2023-41898 in Home Assistant
Summary
by MITRE • 10/25/2023
Home assistant is an open source home automation. The Home Assistant Companion for Android app up to version 2023.8.2 is vulnerable to arbitrary URL loading in a WebView. This enables all sorts of attacks, including arbitrary JavaScript execution, limited native code execution, and credential theft. This issue has been patched in version 2023.9.2 and all users are advised to upgrade. There are no known workarounds for this vulnerability. This issue is also tracked as GitHub Security Lab (GHSL) Vulnerability Report: `GHSL-2023-142`.
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Analysis
by VulDB Data Team • 11/11/2023
The vulnerability CVE-2023-41898 affects the Home Assistant Companion for Android application, which serves as a critical interface for users to interact with their home automation systems remotely. This mobile application acts as a bridge between users and their smart home environments, making it a prime target for attackers seeking to compromise home automation ecosystems. The vulnerability exists within the WebView component of the application, which is responsible for rendering web content and facilitating communication between the mobile application and web-based home assistant interfaces. The flaw represents a significant security risk as it allows malicious actors to manipulate how web content is loaded and executed within the application's context.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the WebView configuration. When the application processes URLs for display within the WebView, it fails to properly validate or filter user-supplied input, creating an opportunity for attackers to inject malicious URLs or web content. This weakness directly maps to CWE-20, which describes improper input validation, and CWE-79, which addresses cross-site scripting vulnerabilities. The vulnerability enables a range of attack vectors including arbitrary JavaScript execution, where malicious code can be injected and run within the WebView context, and limited native code execution that could potentially leverage the Android application's permissions and capabilities. The WebView's trust model appears to be compromised, allowing loaded content to execute with elevated privileges within the application's security boundaries.
The operational impact of this vulnerability extends far beyond simple web content rendering issues, as it fundamentally compromises the security posture of home automation systems. Attackers could exploit this vulnerability to steal user credentials, session tokens, or other sensitive authentication data that the application might handle during normal operation. The vulnerability also enables man-in-the-middle attacks where malicious actors can intercept and manipulate communications between the user's device and their home automation systems. This creates a dangerous scenario where attackers could gain unauthorized access to smart home devices, potentially leading to privacy violations, physical security risks, and unauthorized control of home automation features. The attack surface is particularly concerning given that home automation systems often contain sensitive personal data and control mechanisms for critical home infrastructure.
Security researchers tracking this vulnerability through GitHub Security Lab identified it as GHSL-2023-142, highlighting its severity and impact on the broader Android security ecosystem. The vulnerability affects versions up to 2023.8.2, indicating that users who have not updated to version 2023.9.2 remain exposed to potential exploitation. The lack of known workarounds means that users cannot protect themselves without upgrading the application, which represents a critical gap in the security posture. Organizations and individuals relying on Home Assistant for home automation should immediately implement patch management procedures to ensure all instances of the application are updated to the patched version. The vulnerability demonstrates the importance of proper WebView security configurations and input sanitization in mobile applications, particularly those handling sensitive user data and system controls.
The remediation approach for this vulnerability involves implementing proper URL validation and sanitization within the WebView component, ensuring that all external content is properly filtered and that the application maintains strict control over loaded resources. Security practitioners should review the application's WebView configuration to ensure that appropriate security policies are enforced, including disabling unnecessary features, implementing content security policies, and validating all URL inputs. The patch released in version 2023.9.2 likely includes enhanced input validation mechanisms and improved WebView security settings that prevent the loading of untrusted content. This vulnerability serves as a reminder of the critical importance of maintaining up-to-date security practices in mobile applications, particularly those that interface with sensitive home automation systems and handle user authentication credentials.