CVE-2016-4906 in Garoon Keitai
Summary
by MITRE
Cross-site scripting vulnerability in Cybozu Garoon 3.0.0 to 4.2.2 allows remote attackers to inject arbitrary web script or HTML via "Messages" function of Cybozu Garoon Keitai.
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Analysis
by VulDB Data Team • 12/26/2020
The vulnerability identified as CVE-2016-4906 represents a critical cross-site scripting flaw within Cybozu Garoon versions 3.0.0 through 4.2.2, specifically affecting the Keitai component's Messages function. This weakness enables remote attackers to execute malicious web scripts or HTML code within the context of other users' browsers, potentially compromising the entire application ecosystem. The vulnerability stems from inadequate input validation and output encoding mechanisms within the messaging functionality, creating an attack surface where untrusted data flows directly into web pages without proper sanitization. The affected system components operate within a web application framework that processes user-generated content through the Keitai mobile interface, making it particularly dangerous as mobile users may be more susceptible to such attacks due to limited security awareness and the inherently less secure mobile browsing environment.
The technical exploitation of this vulnerability occurs when attackers submit malicious input through the Messages function, which then gets rendered without proper HTML escaping or sanitization. This flaw falls under CWE-79, which specifically addresses Cross-Site Scripting vulnerabilities, and aligns with ATT&CK technique T1566.001 for initial access through spearphishing attachments or links. The vulnerability's impact extends beyond simple script injection as it can potentially enable session hijacking, data theft, and privilege escalation attacks. When users view the malicious messages, their browsers execute the injected scripts within the context of the legitimate Garoon application, allowing attackers to access session cookies, modify application data, or redirect users to malicious sites. The attack vector is particularly concerning because it leverages the legitimate messaging functionality that users regularly interact with, making detection more difficult and increasing the likelihood of successful exploitation.
The operational impact of CVE-2016-4906 is substantial for organizations using affected Cybozu Garoon versions, as it creates persistent security risks that can compromise entire user bases. Attackers can exploit this vulnerability to gain unauthorized access to sensitive corporate communications, potentially leading to data breaches, intellectual property theft, and regulatory compliance violations. The vulnerability affects organizations that rely on mobile messaging capabilities within their collaboration platforms, making it particularly dangerous for enterprises with mobile workforce components. Organizations may experience reputational damage, regulatory penalties, and financial losses due to successful exploitation. The vulnerability's persistence means that once exploited, attackers can maintain access and continue to leverage the compromised system for extended periods. Security teams must also contend with the challenge of identifying and remediating this vulnerability across multiple systems, as the mobile interface component may be deployed across various organizational units and platforms.
Mitigation strategies for CVE-2016-4906 require immediate action including upgrading to patched versions of Cybozu Garoon, implementing proper input validation and output encoding mechanisms, and deploying web application firewalls to detect and block malicious payloads. Organizations should also consider implementing content security policies to prevent script execution and establish monitoring procedures for unusual messaging patterns. The remediation process must include thorough testing of patched versions to ensure compatibility and proper functionality of the messaging system. Security teams should conduct comprehensive vulnerability assessments to identify any other potential XSS vulnerabilities within the organization's web applications and implement defense-in-depth strategies. Additionally, user education programs should be established to raise awareness about phishing attempts and suspicious messaging patterns, as the vulnerability can be exploited through social engineering approaches that trick users into clicking malicious links or entering compromised content. Organizations should also implement regular security audits and penetration testing to identify similar vulnerabilities in their web applications and maintain up-to-date security patches across all system components.