CVE-2023-46267 in Roundcube
Summary
by MITRE • 10/25/2023
Roundcube before 1.4.15, 1.5.x before 1.5.5, and 1.6.x before 1.6.4 allows XSS via a text/html e-mail message containing an SVG image with a USE element. This is related to wash_uri in rcube_washtml.php.
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Analysis
by VulDB Data Team • 10/25/2023
This vulnerability affects Roundcube webmail applications across multiple versions including 1.4.14 and earlier, 1.5.4 and earlier, and 1.6.3 and earlier. The flaw stems from insufficient input validation and sanitization of HTML content within email messages, specifically when processing text/html email bodies that contain embedded SVG images with USE elements. The vulnerability is particularly concerning because it leverages the wash_uri function located in the rcube_washtml.php file, which is responsible for sanitizing HTML content but fails to properly handle certain SVG constructs that can execute malicious scripts.
The technical implementation of this vulnerability involves the manipulation of SVG (Scalable Vector Graphics) elements within email messages. When an SVG image contains a USE element that references external resources or includes malicious script content, the sanitization process fails to properly neutralize these constructs. This allows attackers to embed malicious code within seemingly benign email attachments or inline images that appear to be standard SVG graphics. The USE element in SVG can reference external resources or contain script content that executes when the SVG is rendered in a web browser, creating a cross-site scripting attack vector.
The operational impact of this vulnerability is significant as it enables attackers to execute arbitrary JavaScript code within the context of a victim's web browser session. This could allow for session hijacking, credential theft, or redirection to malicious websites. Since the vulnerability affects the core email rendering functionality of Roundcube, any user who views a maliciously crafted email message containing the vulnerable SVG content could be compromised. The attack requires no special privileges or authentication, making it particularly dangerous as it can be exploited through standard email delivery mechanisms.
The vulnerability aligns with CWE-79 which describes Cross-Site Scripting flaws, and specifically relates to the improper neutralization of script-related HTML tags. From an ATT&CK perspective, this maps to T1566.001 - Phishing: Spearphishing Attachment, where attackers leverage email attachments or embedded content to deliver malicious payloads. Organizations using Roundcube webmail systems are particularly at risk as the vulnerability affects the core rendering engine that processes email content, making it a critical security concern that requires immediate remediation through version upgrades to 1.4.15, 1.5.5, or 1.6.4 respectively. The fix implemented in these versions addresses the insufficient sanitization of SVG elements by properly validating and neutralizing USE elements within embedded graphics content, preventing the execution of malicious scripts during email rendering operations.
This vulnerability demonstrates the complexity of modern web application security where even seemingly innocuous features like embedded graphics can become attack vectors. The issue highlights the importance of comprehensive input validation and the need for robust sanitization of all user-provided content, particularly in applications that handle email and web-based communications. Organizations should implement immediate patching procedures and consider additional security measures such as email content filtering and user education to mitigate the risk of exploitation. The vulnerability also underscores the necessity of regular security assessments and vulnerability management processes to identify and remediate similar issues before they can be exploited by malicious actors in the wild.