CVE-2004-2704 in Hastymail
Summary
by MITRE
Hastymail 1.0.1 and earlier (stable) and 1.1 and earlier (development) does not send the "attachment" parameter in the Content-Disposition field for attachments, which causes the attachment to be rendered inline by Internet Explorer when the victim clicks the download link, which facilitates cross-site scripting (XSS) and possibly other attacks.
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Analysis
by VulDB Data Team • 04/22/2019
The vulnerability described in CVE-2004-2704 affects Hastymail email client versions 1.0.1 and earlier in the stable release and 1.1 and earlier in the development release. This security flaw resides in the improper handling of email attachments within the application's Content-Disposition header implementation. The issue specifically manifests when the application fails to include the "attachment" parameter in the Content-Disposition field for email attachments. This omission creates a critical security gap that enables malicious actors to exploit vulnerabilities in web browsers, particularly Internet Explorer, by manipulating how attachments are rendered when users click download links.
The technical flaw stems from the application's failure to properly construct HTTP headers for email attachments. When an email contains an attachment, the Content-Disposition header should explicitly specify whether the content should be displayed inline or treated as a downloadable attachment. The absence of the "attachment" parameter in this header causes Internet Explorer to interpret the attachment content as inline content rather than a downloadable file. This misinterpretation creates a pathway for cross-site scripting attacks because the browser renders the attachment content directly within the web page context, allowing malicious code embedded in the attachment to execute in the user's browsing session.
The operational impact of this vulnerability extends beyond simple XSS attacks to potentially enable more sophisticated exploitation techniques. When Internet Explorer renders the attachment inline, it processes the content within the same security context as the web page, creating opportunities for attackers to inject malicious scripts that can access user sessions, steal cookies, or perform unauthorized actions on behalf of the victim. This vulnerability particularly affects users of Internet Explorer who are browsing email content containing malicious attachments, as the browser's rendering engine processes the attachment content with elevated privileges relative to the normal download behavior.
This vulnerability aligns with CWE-20, which describes improper input validation, and specifically relates to CWE-79, Cross-site Scripting, as the flaw enables malicious code execution through web content rendering. The issue also maps to ATT&CK technique T1203, Exploitation for Client Execution, as it enables attackers to execute malicious code on victim machines through web-based email attachments. Additionally, the vulnerability demonstrates characteristics of T1059, Command and Scripting Interpreter, as the execution of malicious content occurs through script processing within the browser context.
The primary mitigation strategy involves updating to a patched version of Hastymail where the Content-Disposition header properly includes the attachment parameter. System administrators should implement comprehensive patch management procedures to ensure all instances of the vulnerable software are updated promptly. Organizations should also consider implementing web application firewalls that can detect and block suspicious Content-Disposition header configurations. Browser security configurations should be reviewed to ensure proper handling of email attachments, and users should be educated about the risks of clicking suspicious links in email messages. Network monitoring should be enhanced to detect unusual attachment handling patterns that might indicate exploitation attempts. The vulnerability underscores the importance of proper HTTP header implementation in web applications and the critical need for security-conscious development practices that consider browser-specific rendering behaviors and their associated security implications.