CVE-2019-14756 in KaiOS
Summary
by MITRE
An issue was discovered in KaiOS 1.0, 2.5, and 2.5.12.5. The pre-installed Email application is vulnerable to HTML and JavaScript injection attacks. An attacker can send a specially crafted email to the victim that will inject HTML into the email application's UI as soon as the email is opened. At a bare minimum, this allows an attacker to take control over the Email application's UI (e.g., display a malicious prompt to the user asking them to re-enter their email credentials) and also allows an attacker to abuse any of the privileges available to the mobile application.
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Analysis
by VulDB Data Team • 09/15/2020
The vulnerability identified as CVE-2019-14756 represents a critical security flaw in the KaiOS operating system versions 1.0, 2.5, and 2.5.12.5 affecting the pre-installed email application. This issue stems from insufficient input validation and output encoding within the email client's rendering engine, creating a pathway for malicious actors to execute cross-site scripting attacks through email messages. The vulnerability manifests when the email application processes incoming messages containing specially crafted HTML and JavaScript code without proper sanitization, allowing attackers to inject malicious content directly into the application's user interface. This represents a classic case of improper input handling that aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities. The attack vector is particularly concerning as it requires no additional privileges or complex exploitation techniques beyond sending a malicious email, making it accessible to threat actors with minimal technical expertise.
The technical impact of this vulnerability extends beyond simple UI manipulation, as it provides attackers with the ability to hijack the email application's interface and potentially escalate privileges. When victims open the malicious email, the injected HTML content is rendered directly within the application's display layer, enabling attackers to create convincing phishing interfaces that can deceive users into revealing sensitive information such as email credentials. The vulnerability's severity is amplified by the fact that the email application operates with elevated privileges within the KaiOS environment, meaning that successful exploitation could grant attackers access to additional system resources and capabilities available to mobile applications. This privilege escalation capability places the vulnerability in the ATT&CK framework under the T1056.001 technique for Input Capture, specifically targeting credential access through malicious UI manipulation. The attack surface is further expanded by the fact that KaiOS devices often serve as mobile communication platforms, making the potential for widespread exploitation significant.
The operational consequences of CVE-2019-14756 are substantial for organizations and individuals using KaiOS-based devices, particularly in enterprise environments where mobile communication security is paramount. The vulnerability undermines the fundamental security assumptions of mobile email clients by allowing attackers to bypass traditional security boundaries through simple email delivery. This creates a persistent threat vector that can be exploited repeatedly against users who open infected emails, potentially leading to credential theft, data exfiltration, and further compromise of connected systems. The vulnerability affects not only individual users but also enterprise communication channels, as attackers can craft targeted campaigns to exploit specific user groups or organizations. Security teams must consider the implications of this vulnerability in their risk assessments, particularly when evaluating the security posture of mobile device management programs and mobile security solutions that may not adequately protect against UI-based attacks. The remediation challenges are significant as the vulnerability exists within the operating system's core email application, requiring either system updates or application-level workarounds to mitigate the risk effectively.
Mitigation strategies for CVE-2019-14756 should focus on both immediate protective measures and long-term architectural improvements. Organizations should implement email filtering solutions that can detect and quarantine potentially malicious HTML content before it reaches end users, while also considering the deployment of mobile device management solutions that can enforce security policies and monitor for suspicious activity. The implementation of content security policies within the email application itself could provide additional protection by restricting the execution of embedded scripts and limiting HTML rendering capabilities. Security awareness training for users becomes crucial in preventing successful exploitation, particularly in recognizing social engineering elements that attackers might employ in conjunction with this vulnerability. System administrators should also consider implementing network-level protections such as web application firewalls and email security gateways that can detect and block malicious payloads before they reach vulnerable devices. The vulnerability highlights the importance of secure coding practices and input validation in mobile application development, emphasizing the need for comprehensive security testing throughout the development lifecycle to prevent similar issues from emerging in future versions of the KaiOS platform.