CVE-2024-28063: Totemo Totemomail XSS Vulnerability

CVE-2024-28063 Overview

CVE-2024-28063 is a reflected Cross-Site Scripting (XSS) vulnerability discovered in Kiteworks Totemomail, a secure email communication platform. The vulnerability exists in the /responsiveUI/EnvelopeOpenServlet endpoint, where the envelopeRecipient parameter fails to properly sanitize user-supplied input before reflecting it back in the HTTP response. This allows attackers to inject malicious JavaScript code that executes in the context of a victim's browser session.

Critical Impact

Attackers can exploit this reflected XSS vulnerability to steal session cookies, capture user credentials, perform actions on behalf of authenticated users, or redirect victims to malicious websites. Given that Totemomail handles sensitive email communications, successful exploitation could lead to unauthorized access to confidential correspondence.

Affected Products

• Totemo Totemomail through version 7.0.0
• All prior versions of Totemomail utilizing the /responsiveUI/EnvelopeOpenServlet endpoint

Discovery Timeline

• 2024-05-18 - CVE-2024-28063 published to NVD
• 2025-06-17 - Last updated in NVD database

Technical Details for CVE-2024-28063

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The flaw occurs when the EnvelopeOpenServlet component processes the envelopeRecipient parameter without adequate input validation or output encoding. When a user clicks on a maliciously crafted link containing JavaScript payload in the envelopeRecipient parameter, the server reflects this unsanitized input directly into the HTML response, causing the browser to execute the injected script.

The attack requires user interaction—specifically, the victim must be tricked into clicking a malicious link. Once clicked, the malicious script executes within the security context of the Totemomail application, inheriting the victim's session and permissions.

Root Cause

The root cause of this vulnerability is insufficient input validation and output encoding in the EnvelopeOpenServlet servlet. The application directly incorporates user-controlled data from the envelopeRecipient parameter into the HTML response without properly escaping special characters such as <, >, ", and '. This allows attackers to break out of the expected data context and inject arbitrary HTML or JavaScript code.

Attack Vector

The attack is conducted over the network and requires an attacker to craft a malicious URL containing JavaScript code in the envelopeRecipient parameter. The attacker then distributes this URL through phishing emails, social engineering, or by embedding it in third-party websites. When an authenticated Totemomail user clicks the link, the malicious script executes in their browser context.

The exploitation mechanism targets the /responsiveUI/EnvelopeOpenServlet endpoint, injecting script content through the envelopeRecipient parameter. For detailed technical information about the vulnerability, refer to the Objectif Securite Advisory.

Detection Methods for CVE-2024-28063

Indicators of Compromise

• HTTP requests to /responsiveUI/EnvelopeOpenServlet containing script tags or JavaScript event handlers in the envelopeRecipient parameter
• Presence of encoded JavaScript payloads (URL encoding, HTML entity encoding) in request URLs targeting the vulnerable endpoint
• Unusual outbound connections from user browsers following visits to Totemomail application pages
• Browser console errors or unexpected script execution warnings when accessing Totemomail

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block requests containing XSS patterns in the envelopeRecipient parameter
• Monitor web server access logs for suspicious requests to /responsiveUI/EnvelopeOpenServlet with malformed or encoded parameters
• Deploy browser-based Content Security Policy (CSP) violation reporting to detect inline script execution attempts
• Configure SIEM alerts for patterns indicative of XSS exploitation targeting the Totemomail application

Monitoring Recommendations

• Enable verbose logging for the EnvelopeOpenServlet component to capture all parameter values in requests
• Implement real-time alerting for requests containing common XSS payload signatures such as <script>, javascript:, or onerror=
• Monitor for unusual user session activity that may indicate session hijacking following XSS exploitation
• Review Content Security Policy violation reports for attempts to execute unauthorized inline scripts

How to Mitigate CVE-2024-28063

Immediate Actions Required

• Upgrade Totemomail to a patched version if available from Kiteworks/Totemo
• Implement input validation at the web application firewall level to block malicious requests to the vulnerable endpoint
• Deploy Content Security Policy headers to restrict inline script execution and mitigate XSS impact
• Educate users about the risks of clicking suspicious links, especially those pointing to internal applications

Patch Information

Organizations using Totemomail should contact Kiteworks (formerly Totemo) for information about security updates addressing this vulnerability. Review the Objectif Securite Advisory for additional remediation guidance. Ensure that any patches are tested in a staging environment before production deployment.

Workarounds

• Configure WAF rules to sanitize or block requests to /responsiveUI/EnvelopeOpenServlet containing potentially malicious characters in the envelopeRecipient parameter
• Implement strict Content Security Policy headers including script-src 'self' to prevent execution of injected scripts
• Consider restricting access to the vulnerable endpoint to trusted IP ranges or authenticated users only until a patch is applied
• Enable HttpOnly and Secure flags on session cookies to reduce the impact of potential session theft

# Example WAF rule configuration (ModSecurity)
SecRule ARGS:envelopeRecipient "@rx (?i)(<script|javascript:|onerror=|onload=)" \
    "id:2024028063,phase:2,deny,status:403,msg:'CVE-2024-28063 XSS Attempt Blocked'"