CVE-2019-9147 in Mailvelope
Summary
by MITRE
Mailvelope prior to 3.1.0 is vulnerable to a clickjacking attack against the settings page. As the settings page is intended to be accessible from web applications, the browser's extension isolation mechanisms are disabled (web_accessible_resources). Mailvelope implements additional measures to prevent web applications from directly embedding the settings page, but this mechanism can be bypassed.
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Analysis
by VulDB Data Team • 10/24/2023
The vulnerability identified as CVE-2019-9147 affects Mailvelope versions prior to 310 and represents a critical clickjacking flaw targeting the extension's settings page. This security weakness arises from the design decision to make the settings page accessible to web applications through the browser's extension isolation mechanisms, specifically by utilizing web_accessible_resources. The fundamental issue stems from the extension's architecture where it intentionally disables certain browser security boundaries to enable legitimate web application integration, creating an attack surface that adversaries can exploit. The vulnerability manifests because Mailvelope implemented additional protective measures to prevent direct embedding of the settings page by web applications, but these safeguards contain a critical flaw that allows attackers to bypass the intended restrictions.
Clickjacking attacks exploit the ability of malicious web pages to overlay invisible or transparent elements over legitimate user interface components, tricking users into performing unintended actions. In this case, the attack vector targets the Mailvelope settings page which contains sensitive configuration options and potentially dangerous operations. The bypass mechanism likely involves sophisticated techniques that manipulate the browser's rendering context or exploit timing issues in the extension's permission checks. Attackers can create malicious web pages that appear to be legitimate Mailvelope interfaces while actually executing unauthorized operations through the vulnerable settings page. This vulnerability directly impacts the principle of least privilege and user consent, as users may unknowingly perform actions on their encryption settings or key management functions while believing they are interacting with a different interface.
The operational impact of CVE-2019-9147 extends beyond simple data exposure to encompass potential compromise of the entire email encryption ecosystem managed by Mailvelope. An attacker who successfully exploits this vulnerability could modify encryption settings, alter key configurations, or even inject malicious code into the extension's operational environment. The bypass of web_accessible_resources protections represents a fundamental failure in the extension's security model, potentially allowing attackers to gain elevated privileges within the browser context where Mailvelope operates. This vulnerability affects not only the privacy of email communications but also the integrity of the encryption infrastructure, as malicious actors could manipulate key management operations or configuration parameters that govern how emails are encrypted and decrypted. The implications are particularly severe given that email encryption systems are often used for highly sensitive communications, making this vulnerability a significant threat to user security and trust in the extension.
Mitigation strategies for CVE-2019-9147 require immediate upgrading to Mailvelope version 3.1.0 or later, which contains the necessary patches to address the clickjacking vulnerability. Organizations and individuals should implement additional security measures including browser security extensions that detect and prevent clickjacking attempts, regular security audits of web applications that interact with Mailvelope, and user education about suspicious website behaviors. The fix likely involves strengthening the validation mechanisms that prevent unauthorized embedding of the settings page, implementing proper frame-busting techniques, or enhancing the extension's content security policies. From a cybersecurity perspective, this vulnerability highlights the importance of defense-in-depth strategies and the need for continuous security assessment of browser extensions. The issue aligns with CWE-1021, which describes improper restriction of operations within a bounds of a memory buffer, and maps to ATT&CK technique T1059.001 for command and scripting interpreter, as attackers could potentially leverage this vulnerability to execute malicious commands through compromised extension settings. Organizations should also consider implementing monitoring solutions that detect unusual patterns in extension usage or unauthorized configuration changes that might indicate exploitation attempts.