CVE-2019-11380 in ES File Explorer File Manager
Summary
by MITRE
The master-password feature in the ES File Explorer File Manager application 4.2.0.1.3 for Android can be bypassed via a com.estrongs.android.pop.ftp.ESFtpShortcut intent, leading to remote FTP access to the entirety of local storage.
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Analysis
by VulDB Data Team • 12/13/2023
The vulnerability CVE-2019-11380 represents a critical security flaw in the ES File Explorer File Manager application version 4.2.0.1.3 for Android platforms. This issue specifically targets the master-password protection mechanism that was designed to secure user data and prevent unauthorized access to local storage. The flaw exists within the application's intent handling system, where a specific component named com.estrongs.android.pop.ftp.ESFtpShortcut can be exploited to circumvent the authentication requirements that should normally protect the device's file system. The vulnerability stems from inadequate input validation and improper access control implementation within the application's intent processing framework, creating a direct pathway for unauthorized users to gain complete access to all local storage content.
The technical exploitation of this vulnerability occurs through the manipulation of Android intents, specifically targeting the ESFtpShortcut intent component. When this intent is triggered, it bypasses the master-password authentication mechanism entirely, allowing attackers to establish remote FTP connections to the device's local storage without proper authorization. This represents a fundamental breakdown in the application's security architecture, as the intent-based access control mechanism fails to properly validate the authenticity of the requesting component or user credentials. The flaw aligns with CWE-284, which addresses improper access control vulnerabilities, and demonstrates how Android intent systems can be abused when proper validation checks are omitted. The vulnerability essentially creates a backdoor through which any attacker with knowledge of the specific intent can access all files stored locally on the device, potentially exposing sensitive personal data, documents, photos, and other confidential information.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it provides attackers with complete control over the device's local storage through remote FTP connections. This means that malicious actors can not only read sensitive files but also potentially modify, delete, or exfiltrate data without the user's knowledge or consent. The implications are particularly severe for mobile devices where users often store personal information, work documents, and confidential data that should remain protected. From an attacker's perspective, this vulnerability allows for persistent access to the device's file system, enabling data collection, potential lateral movement within networks, and the possibility of using the compromised device as a pivot point for further attacks. The attack surface is expanded through the use of the ATT&CK framework's T1059.007 technique, which involves the use of remote access tools and services to maintain persistent access to compromised systems.
Mitigation strategies for this vulnerability require immediate action from both users and developers. Users should uninstall the affected version of ES File Explorer and avoid using applications with known security flaws until proper updates are available. The recommended approach involves implementing proper input validation and authentication checks within intent handlers to ensure that only authorized components can access sensitive functionality. Security professionals should enforce strict access control policies and validate all incoming intents before processing them, particularly those that provide access to local storage or network services. Additionally, application developers should implement proper privilege separation and ensure that sensitive operations require explicit user authentication before execution. The vulnerability highlights the importance of secure intent handling practices and demonstrates how seemingly minor flaws in Android application design can create significant security risks. Organizations should also consider implementing mobile device management solutions that can monitor for and block suspicious intent usage patterns, while security teams should regularly audit application permissions and intent handling mechanisms to prevent similar vulnerabilities from being introduced in future versions.