CVE-2018-14955 in SquirrelMail
Summary
by MITRE
The mail message display page in SquirrelMail through 1.4.22 has XSS via SVG animations (animate to attribute).
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Analysis
by VulDB Data Team • 05/01/2023
The vulnerability identified as CVE-2018-14955 represents a cross-site scripting weakness in SquirrelMail version 1.4.22 and earlier, specifically affecting the mail message display functionality. This issue arises from insufficient input validation and sanitization of HTML content within email messages, creating an avenue for malicious actors to execute arbitrary JavaScript code in the context of a victim's browser session. The vulnerability is particularly concerning as it leverages SVG animation elements to bypass traditional security mechanisms that might otherwise detect or block standard XSS payloads.
The technical flaw manifests through the improper handling of SVG elements containing animate attributes within email messages. When SquirrelMail renders email content, it fails to adequately sanitize or escape SVG animation tags that include the to attribute, which can be manipulated to execute malicious JavaScript code. This particular exploitation vector is significant because SVG elements are often processed by web browsers with less stringent security restrictions compared to traditional HTML content, making them a preferred target for attackers seeking to bypass security controls. The vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws in web applications.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, and data exfiltration. An attacker could craft a malicious email containing SVG animation code that, when viewed by a victim using the vulnerable SquirrelMail version, would execute JavaScript in the victim's browser context. This could lead to unauthorized access to email accounts, modification of email content, or redirection to phishing sites. The vulnerability is particularly dangerous in enterprise environments where SquirrelMail is commonly used for internal email communication, as it could facilitate lateral movement and persistent access within network perimeters.
Organizations should prioritize immediate remediation by upgrading to SquirrelMail version 1.4.23 or later, which includes proper input sanitization for SVG content. Additional mitigations include implementing strict Content Security Policy headers that restrict script execution, enabling MIME-type validation for email attachments, and deploying web application firewalls that can detect and block malicious SVG content. From an ATT&CK framework perspective, this vulnerability maps to technique T1059.007 for script execution and T1566 for phishing attacks, as attackers could leverage this vulnerability to establish initial access and maintain persistence through compromised email accounts. Regular security assessments and input validation testing should be implemented to prevent similar vulnerabilities in other web applications handling user-generated content.