CVE-2005-0420 in Exchange
Summary
by MITRE
Microsoft Outlook Web Access (OWA), when used with Exchange, allows remote attackers to redirect users to arbitrary URLs for login via a link to the owalogon.asp application.
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Analysis
by VulDB Data Team • 08/26/2024
Microsoft Outlook Web Access represents a critical web-based interface for email access within Exchange environments, serving as a primary communication channel for millions of users worldwide. The vulnerability identified in CVE-2005-0420 specifically targets the authentication mechanism of OWA through the owalogon.asp application, which processes login requests and redirects users to designated URLs upon successful authentication. This flaw exists within the URL redirection logic that fails to properly validate or sanitize input parameters passed to the authentication endpoint, creating an opportunity for malicious actors to manipulate the redirection behavior.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL containing a crafted redirect parameter that points to an attacker-controlled website instead of the legitimate Exchange server. When a victim clicks such a link and authenticates through the vulnerable OWA interface, the authentication process will redirect them to the attacker's specified destination rather than returning them to the intended Exchange web interface. This vulnerability aligns with CWE-601, which specifically addresses URL redirection and forwarding vulnerabilities where applications redirect users to untrusted domains without proper validation. The flaw essentially allows for open redirect conditions that can be leveraged in phishing attacks, credential theft operations, and social engineering campaigns.
The operational impact of this vulnerability extends beyond simple redirection, as it enables sophisticated attack vectors that can compromise user sessions and facilitate unauthorized access to corporate email systems. Attackers can craft convincing phishing pages that mimic legitimate Exchange interfaces, tricking users into entering credentials that are then captured by the malicious server. This vulnerability particularly affects organizations that rely heavily on web-based email access, as it undermines the trust model between users and the authentication system. The attack surface is significantly expanded since the vulnerability exists in the authentication flow itself, making it a prime target for initial compromise in larger attack campaigns. According to ATT&CK framework, this vulnerability maps to T1566, which covers Phishing techniques, and T1071, which addresses application layer protocols, specifically targeting web-based authentication mechanisms.
Organizations can mitigate this vulnerability by implementing proper input validation and sanitization on all redirect parameters within the OWA authentication flow, ensuring that only URLs from trusted domains are accepted. The recommended approach involves maintaining a whitelist of approved redirect destinations and implementing strict validation of all URL parameters before processing. Microsoft released patches for this vulnerability as part of their regular security updates, and organizations should ensure all Exchange servers are updated to the latest security patches. Network-level controls such as web application firewalls can provide additional protection by monitoring and filtering suspicious redirect patterns. Additionally, user education programs should emphasize the importance of verifying URLs before authentication, particularly when accessing email services through web interfaces, as this vulnerability can be effectively exploited through social engineering techniques that rely on user trust in seemingly legitimate authentication pages.