CVE-2020-5541 in CyberMail
Summary
by MITRE
Open redirect vulnerability in CyberMail Ver.6.x and Ver.7.x allows remote attackers to redirect users to arbitrary sites and conduct phishing attacks via a specially crafted URL.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/25/2020
The CVE-2020-5541 vulnerability represents a critical open redirect flaw affecting CyberMail versions 6.x and 7.x, demonstrating a fundamental security weakness in web application input validation and output encoding mechanisms. This vulnerability classifies under CWE-601 which specifically addresses open redirect vulnerabilities, where applications fail to properly validate or sanitize user-supplied redirect URLs. The flaw exists in the application's handling of redirect parameters within HTTP responses, allowing malicious actors to craft URLs that appear legitimate while directing users to attacker-controlled domains. The vulnerability stems from insufficient validation of redirect targets, enabling attackers to exploit the application's trust in its own redirect functionality without proper sanitization of input parameters.
The technical exploitation of this vulnerability occurs when a malicious user crafts a URL containing a redirect parameter that points to an external domain instead of the application's own domain. When users click such links, the application processes the redirect without proper validation, causing users to be silently redirected to phishing sites or malicious domains. This creates a dangerous trust relationship where users believe they are navigating within the legitimate application while actually being directed to attacker-controlled resources. The vulnerability is particularly dangerous because it can be easily weaponized using social engineering techniques, making it a prime candidate for phishing campaigns that leverage the perceived legitimacy of the target application.
The operational impact of CVE-2020-5541 extends beyond simple redirection, creating significant risks for both user security and organizational reputation. Attackers can leverage this vulnerability to conduct sophisticated phishing attacks where victims are redirected to carefully crafted malicious sites designed to capture credentials or install malware. The vulnerability enables man-in-the-middle attack scenarios where users are unknowingly redirected to compromised domains that mimic legitimate application interfaces. Organizations using affected CyberMail versions face potential data breaches, credential theft, and reputational damage as users may unknowingly provide sensitive information to attackers. The vulnerability also creates opportunities for additional attacks such as drive-by downloads or malware distribution through the redirected malicious sites.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements to prevent similar issues. Organizations should implement strict input validation for all redirect parameters, ensuring that any redirect URLs are either validated against a predetermined whitelist of trusted domains or properly encoded to prevent malicious redirection. The application should enforce domain validation checks that verify redirect targets against known legitimate domains before processing redirects. Security patches should be applied immediately to upgrade to versions that address the open redirect flaw, while organizations should also implement web application firewalls with redirect validation capabilities. Additionally, security awareness training should be conducted to educate users about recognizing potential phishing attempts and suspicious redirect behavior. This vulnerability aligns with ATT&CK technique T1566 which covers social engineering tactics including phishing, demonstrating how open redirect vulnerabilities can be weaponized as initial access vectors in broader attack campaigns.