CVE-2019-11928 in WhatsApp Desktop
Summary
by MITRE
An input validation issue in WhatsApp Desktop versions prior to v0.3.4932 could have allowed cross-site scripting upon clicking on a link from a specially crafted live location message.
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Analysis
by VulDB Data Team • 11/12/2020
The vulnerability CVE-2019-11928 represents a critical cross-site scripting flaw in WhatsApp Desktop client versions preceding v0.3.4932, demonstrating how mobile messaging applications can expose users to web-based attacks through seemingly innocuous location sharing features. This issue specifically exploited the application's handling of live location messages, which are designed to share real-time geographical coordinates and movement updates between users. The vulnerability emerged from insufficient input validation mechanisms within the desktop client's message processing pipeline, creating an attack surface where malicious actors could craft specially formatted live location messages that would execute arbitrary JavaScript code when clicked by unsuspecting users.
The technical exploitation of this vulnerability leverages the desktop application's failure to properly sanitize user-provided data within the live location message context. When a user receives a crafted live location message, the application processes the embedded data without adequate validation or sanitization, allowing malicious payloads to be embedded within the location coordinates or associated metadata. This flaw falls under CWE-79, Cross-site Scripting, and more specifically CWE-74, Improper Neutralization of Special Elements in Output Used by a Downstream Component, as the application fails to properly escape or validate user-supplied content before rendering it in the user interface. The vulnerability specifically affects the desktop client's HTML rendering engine, which processes the location data and displays it to users through web-based interfaces, making it susceptible to script injection attacks that could execute in the context of the application's security boundaries.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the ability to perform session hijacking, data exfiltration, and persistent access to user accounts. When a victim clicks on a maliciously crafted link within the live location message, the injected JavaScript code can access the application's local storage, read stored credentials, and potentially establish persistent backdoors through the desktop client's network connections. The attack vector is particularly insidious because live location sharing is a legitimate and frequently used feature, making users less likely to scrutinize such messages, and the attack can occur without requiring any special privileges or complex social engineering beyond sending a single malicious message. This vulnerability directly aligns with ATT&CK technique T1566.001, Phishing, as it exploits the trust users place in location sharing functionality, and T1059.001, Command and Scripting Interpreter, as it enables execution of arbitrary code through JavaScript payloads.
Mitigation strategies for CVE-2019-11928 require immediate application updates to version v0.3.4932 or later, which implements proper input validation and sanitization mechanisms for live location messages. Organizations should also consider implementing network-based protections such as web application firewalls and content filtering solutions that can detect and block malicious JavaScript payloads in real-time. Users must be educated about the risks of clicking links in unsolicited or unexpected location sharing messages, and security teams should monitor for unusual network traffic patterns that might indicate exploitation attempts. The vulnerability highlights the importance of comprehensive input validation across all application components, particularly those that process user-generated content, and demonstrates the need for regular security audits of desktop applications that interface with web technologies. Additionally, implementing proper security boundaries between different application components and using secure coding practices such as output encoding and content security policies would have prevented this vulnerability from manifesting in the first place.