CVE-2019-12367 in App
Summary
by MITRE
The BlueMail application through 1.9.5.36 for Android allows XSS via an event attribute and arbitrary file loading via a src attribute, if the application has the READ_EXTERNAL_STORAGE permission.
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Analysis
by VulDB Data Team • 03/19/2020
The vulnerability identified as CVE-2019-12367 affects the BlueMail Android application version 1.9.5.36 and earlier, presenting significant security risks through cross-site scripting and arbitrary file loading capabilities. This issue arises from insufficient input validation and sanitization mechanisms within the application's handling of event attributes and source attributes, creating pathways for malicious actors to exploit the application's trust model and execute unauthorized operations.
The technical flaw manifests through two primary attack vectors that leverage the application's permission model and HTML parsing capabilities. The first vector involves cross-site scripting through event attributes, where maliciously crafted input can be injected into event handlers such as onclick, onmouseover, or other JavaScript event handlers. This vulnerability stems from inadequate sanitization of user-supplied data before rendering it within the application's interface, allowing attackers to inject malicious JavaScript code that executes in the context of the application's web view. The second vector enables arbitrary file loading via src attributes, which becomes particularly dangerous when the application possesses the READ_EXTERNAL_STORAGE permission. This permission allows the application to access files stored on external storage, creating opportunities for attackers to load malicious content from local files or manipulate file paths to access sensitive data.
The operational impact of this vulnerability extends beyond simple data theft or execution of malicious code. When exploited, these vulnerabilities can lead to full compromise of user data, unauthorized access to sensitive communications, and potential lateral movement within the device's file system. The combination of XSS and arbitrary file loading creates a dangerous attack surface where an attacker could first execute JavaScript to manipulate the application's behavior and then use the file loading capability to access stored credentials, personal documents, or other sensitive information. This vulnerability particularly affects users who have granted the READ_EXTERNAL_STORAGE permission, as it significantly expands the attack surface and potential damage scope.
The vulnerability aligns with CWE-79 Cross-Site Scripting and CWE-22 Improper Limitation of a Pathname to a Restricted Directory, both of which represent fundamental security weaknesses in input validation and access control mechanisms. From an ATT&CK framework perspective, this vulnerability maps to T1059 Command and Scripting Interpreter and T1074 Data Staged, as attackers can execute code through the XSS vector and potentially stage malicious payloads through the file loading capability. The vulnerability also represents a path to privilege escalation and persistence mechanisms when combined with the application's storage access permissions, as attackers can create malicious files in accessible directories and then load them through the vulnerable src attribute handling.
Mitigation strategies should focus on implementing comprehensive input sanitization and validation mechanisms throughout the application's codebase. The application must sanitize all user-supplied data before rendering it within HTML contexts, particularly for event attributes that could lead to XSS vulnerabilities. Implementing Content Security Policy headers and using secure coding practices such as output encoding and context-aware escaping can significantly reduce the risk of XSS exploitation. Additionally, the application should implement proper access controls and file path validation to prevent arbitrary file loading, particularly when handling external storage access. The application should also consider implementing least privilege principles for storage permissions, ensuring that the READ_EXTERNAL_STORAGE permission is only granted when absolutely necessary for core functionality. Regular security audits and code reviews focusing on input validation, HTML rendering, and file access mechanisms should be conducted to identify and remediate similar vulnerabilities before they can be exploited by malicious actors.