CVE-2000-0716 in MDaemon
Summary
by MITRE
WorldClient email client in MDaemon 2.8 includes the session ID in the referer field of an HTTP request when the user clicks on a URL, which allows the visited web site to hijcak the session ID and read the user s email.
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Analysis
by VulDB Data Team • 10/13/2025
The vulnerability described in CVE-2000-0716 represents a critical session management flaw in the WorldClient email client component of MDaemon 2.8 email server software. This issue stems from improper handling of HTTP referer headers during web-based email operations, creating a significant security risk that directly impacts user privacy and system integrity. The flaw manifests when users navigate through web-based email interfaces and click on external links, inadvertently exposing their session identifiers to third-party websites through the referer header field.
The technical implementation of this vulnerability involves the WorldClient component's failure to sanitize or remove session identifiers from HTTP referer headers when users initiate web navigation. Session identifiers are typically used to maintain user authentication state across multiple HTTP requests, but when these identifiers are transmitted in clear text within referer headers, they become accessible to any website that receives the HTTP request. This behavior violates fundamental security principles of session management and creates an attack surface that adversaries can exploit to gain unauthorized access to user email accounts. The vulnerability is classified under CWE-200, which addresses information exposure through improper handling of sensitive data, and aligns with ATT&CK technique T1566 for credential access through social engineering and web-based attacks.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables session hijacking attacks that can lead to complete account compromise. When a user clicks on a link from their email client to an external website, the referer header containing the session ID is transmitted along with the request, allowing the target website to capture this identifier. Attackers can then use the stolen session ID to impersonate the legitimate user and access their email content, potentially gaining access to sensitive communications, personal information, and business data. The vulnerability affects all users of MDaemon 2.8 with WorldClient enabled, creating a widespread security risk for organizations relying on this email server solution. This type of attack can result in significant data breaches, privacy violations, and potential regulatory compliance issues under data protection regulations.
Mitigation strategies for CVE-2000-0716 should focus on both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities. The most effective immediate solution involves updating to a patched version of MDaemon that properly sanitizes referer headers or implements secure session management practices. Organizations should also consider implementing referer header filtering at network level or through web application firewalls to prevent session identifiers from being transmitted in HTTP headers. Additionally, security best practices such as implementing secure session management protocols, using HTTPS encryption for all communications, and employing proper input validation techniques can prevent similar vulnerabilities. The vulnerability highlights the importance of following secure coding practices and proper security testing for web applications, particularly those handling authentication and session management. Organizations should also conduct regular security assessments and vulnerability scanning to identify and remediate similar issues in their email infrastructure and web applications, ensuring compliance with industry standards such as those outlined in the OWASP Top Ten and NIST cybersecurity frameworks.