CVE-2016-4068 in RoundCube
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Roundcube Webmail before 1.0.9 and 1.1.x before 1.1.5 allows remote attackers to inject arbitrary web script or HTML via a crafted SVG, a different vulnerability than CVE-2015-8864.
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Analysis
by VulDB Data Team • 11/29/2022
The CVE-2016-4068 vulnerability represents a critical cross-site scripting flaw discovered in Roundcube Webmail, a widely-used open-source web-based email client. This vulnerability affects versions prior to 1.0.9 in the 1.0.x series and 1.1.5 in the 1.1.x series, creating a significant security risk for organizations relying on this email platform. The flaw specifically arises from inadequate input validation and sanitization mechanisms when processing SVG (Scalable Vector Graphics) content, allowing malicious actors to execute arbitrary web scripts or HTML code within the context of a victim's browser session. Unlike CVE-2015-8864 which addressed different XSS vectors, this vulnerability leverages the unique properties of SVG files to bypass traditional security filters that typically focus on more common HTML injection points.
The technical exploitation of this vulnerability occurs when a malicious actor crafts a specially designed SVG file containing embedded malicious code that gets processed by the Roundcube Webmail application. The vulnerability stems from the application's failure to properly sanitize SVG content, particularly elements such as script tags, event handlers, and embedded JavaScript within SVG markup. When a user views an infected email containing this crafted SVG, the browser executes the malicious code within the context of the webmail application, potentially leading to session hijacking, credential theft, or further exploitation of the victim's browser. This represents a CWE-79 (Cross-site Scripting) vulnerability classified under the OWASP Top Ten as a critical web application security risk, specifically targeting the improper neutralization of input during web page generation.
The operational impact of CVE-2016-4068 extends beyond simple script execution, as it provides attackers with a sophisticated vector for conducting advanced persistent threats against organizations using vulnerable Roundcube installations. Attackers can leverage this vulnerability to establish persistent access to user mailboxes, steal sensitive email communications, access contact lists, and potentially escalate privileges within the email infrastructure. The vulnerability's remote nature means that attackers do not require physical access to the target system, making it particularly dangerous for enterprise environments where email serves as a primary communication channel. Security professionals should note that this vulnerability aligns with ATT&CK technique T1059.007 (Command and Scripting Interpreter: JavaScript) and T1566 (Phishing), as it enables the delivery of malicious JavaScript payloads through email channels.
Organizations should implement immediate mitigation strategies including updating to Roundcube versions 1.0.9 or 1.1.5, which contain the necessary patches to address the SVG sanitization issues. Additional protective measures include implementing strict content security policies, deploying web application firewalls to filter suspicious SVG content, and configuring email filters to block potentially malicious attachments. Security teams should also consider implementing monitoring for unusual SVG content processing within their webmail environments and conduct regular security assessments to identify similar vulnerabilities in other web applications. The vulnerability demonstrates the importance of comprehensive input validation across all file types, particularly those with complex parsing requirements like SVG, which can contain multiple attack vectors beyond simple HTML injection points.