CVE-2012-6339 in FTP Server
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the administrative web interface in Cerberus FTP Server before 5.0.6.0 allow (1) remote attackers to inject arbitrary web script or HTML via a log entry that is not properly handled within the Log Manager component, and might allow (2) remote authenticated administrators to inject arbitrary web script or HTML via a Messages field to the servermanager program.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/21/2021
The CVE-2012-6339 vulnerability represents a critical cross-site scripting flaw affecting the administrative web interface of Cerberus FTP Server versions prior to 5.0.6.0. This vulnerability manifests in two distinct attack vectors that exploit the server's inadequate input sanitization mechanisms within its administrative components. The first vector targets the Log Manager component where log entries containing malicious scripts are not properly escaped or validated before being rendered in the web interface, while the second vector allows authenticated administrators to inject malicious code through the Messages field of the servermanager program. Both vulnerabilities stem from the server's failure to implement proper output encoding and input validation controls in its administrative web interface, creating persistent XSS attack surfaces that can be exploited by remote attackers.
The technical exploitation of these vulnerabilities occurs through the manipulation of user-controllable input fields within the administrative interface. When malicious scripts are injected into log entries or message fields, they are subsequently rendered in the web browser without proper sanitization, allowing attackers to execute arbitrary JavaScript code within the context of authenticated sessions. This creates a severe security risk as the injected scripts can access session cookies, modify administrative settings, or redirect users to malicious sites. The vulnerability specifically aligns with CWE-79, which describes cross-site scripting flaws, and demonstrates the classic pattern of insufficient input validation and output encoding in web applications. The attack surfaces are particularly dangerous because they target administrative interfaces where attackers can potentially gain elevated privileges and control over the entire FTP server configuration.
The operational impact of CVE-2012-6339 extends beyond simple script injection, as it can lead to complete administrative compromise of the FTP server. An attacker who successfully exploits these vulnerabilities can maintain persistent access to the administrative interface, modify user permissions, access sensitive server configurations, and potentially use the compromised administrative session to launch further attacks against the internal network. The vulnerability also poses risks to other users of the FTP server, as malicious scripts could be used to steal session information or redirect users to phishing sites. From an ATT&CK framework perspective, this vulnerability maps to T1078 for valid accounts and T1566 for phishing, as attackers can leverage compromised administrative sessions to establish persistence and conduct further reconnaissance. The vulnerability affects the integrity and availability of the FTP server's administrative functions, potentially leading to data loss or unauthorized access to stored files.
Organizations using affected versions of Cerberus FTP Server should immediately implement the available security patches to address these vulnerabilities. The recommended mitigation strategy includes upgrading to version 5.0.6.0 or later, which contains proper input validation and output encoding controls. Additionally, administrators should implement network segmentation to limit access to the administrative interface, enforce strict access controls, and monitor log entries for suspicious activity. Security monitoring should focus on identifying unusual patterns in log entries and message fields that could indicate exploitation attempts. Organizations should also consider implementing web application firewalls to detect and block malicious script injection attempts, while establishing regular security audits of administrative interfaces to identify similar vulnerabilities. The implementation of proper input validation frameworks and output encoding mechanisms should be prioritized to prevent similar issues in other components of the FTP server's administrative interface.