CVE-2018-9140 in Mobile Device
Summary
by MITRE
On Samsung mobile devices with M(6.0) software, the Email application allows XSS via an event attribute and arbitrary file loading via a src attribute, aka SVE-2017-10747.
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Analysis
by VulDB Data Team • 01/18/2020
The vulnerability identified as CVE-2018-9140 represents a critical cross-site scripting flaw within Samsung's Email application affecting devices running Android Marshmallow version 6.0 and earlier. This vulnerability stems from insufficient input validation and sanitization mechanisms within the email client's handling of HTML content, particularly when processing email messages that contain maliciously crafted markup. The flaw specifically manifests through two distinct attack vectors that together create a comprehensive exploitation pathway for malicious actors targeting Samsung mobile users.
The technical implementation of this vulnerability involves the Email application's failure to properly sanitize HTML attributes when rendering email content, particularly the event attribute and src attribute processing. When a malicious email contains HTML code with event handlers such as onclick, onmouseover, or other JavaScript event attributes, the application does not adequately filter or escape these elements before rendering them in the user interface. Additionally, the application's handling of the src attribute allows for arbitrary file loading, enabling attackers to reference external resources that could contain malicious payloads or redirect users to harmful websites. This dual vulnerability creates a dangerous combination where attackers can both execute malicious scripts within the context of the email application and potentially load additional malicious content from remote servers.
The operational impact of CVE-2018-9140 extends beyond simple script execution, as it provides attackers with a foothold for more sophisticated attacks against Samsung mobile device users. The vulnerability affects a significant portion of Samsung's user base running Android 6.0, which was widely deployed across various Samsung Galaxy devices including the Galaxy S6, S7, and other models. Attackers can leverage this vulnerability to perform phishing attacks, steal user credentials, or deliver additional malware payloads through the email client interface. The exploitation of this vulnerability aligns with ATT&CK technique T1566.001 for Phishing and T1059.007 for Command and Scripting Interpreter, as it enables attackers to execute malicious code through email-based delivery mechanisms. The vulnerability also maps to CWE-79 which describes Cross-Site Scripting, and CWE-20 which covers Improper Input Validation, highlighting the fundamental security flaws in the application's data handling processes.
Mitigation strategies for this vulnerability should encompass both immediate patching and defensive measures. Samsung released security updates addressing this vulnerability in subsequent software releases, and users should immediately install available updates to protect their devices. Organizations should implement email filtering solutions that can detect and block malicious HTML content before it reaches users, particularly focusing on filtering for suspicious event attributes and src attribute references. Network administrators should consider implementing web application firewalls and content filtering solutions that can detect and block attempts to exploit this vulnerability. Additionally, user education regarding the dangers of opening suspicious emails and the importance of keeping mobile devices updated remains crucial. The vulnerability demonstrates the importance of proper input validation and output encoding in mobile applications, particularly those handling user-generated content or external data sources. Security professionals should also consider implementing monitoring solutions that can detect anomalous behavior patterns consistent with XSS exploitation attempts. The incident underscores the critical need for comprehensive security testing of mobile applications, particularly those handling email content and user interactions. This vulnerability serves as a reminder of the importance of following secure coding practices and implementing defense-in-depth strategies to protect against both known and emerging threats in mobile environments.