CVE-2007-3769 in SurgeFTP
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the mirrored server management interface in SurgeFTP 2.3a1 allows user-assisted, remote FTP servers to inject arbitrary web script or HTML via a malformed response without a status code, which is reflected to the user in the resulting error message. NOTE: this can be leveraged for root access via a sequence of steps involving web script that creates a new FTP user account.
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Analysis
by VulDB Data Team • 09/05/2018
The vulnerability identified as CVE-2007-3769 represents a critical cross-site scripting flaw within the SurgeFTP 2.3a1 mirrored server management interface. This security weakness stems from inadequate input validation and sanitization mechanisms in the application's handling of FTP server responses. The vulnerability specifically manifests when the FTP client encounters a malformed response lacking a proper status code, creating an opportunity for malicious actors to inject arbitrary web scripts or HTML content into the system. The reflected nature of this XSS attack means that malicious code becomes part of the error message displayed to users, potentially executing in their browser context. This particular implementation flaw exists within the mirrored server management interface, which is designed to provide administrators with a consolidated view of multiple FTP server configurations, thereby expanding the potential attack surface.
The technical exploitation of this vulnerability requires a user-assisted scenario where remote FTP servers can craft malicious responses to manipulate the application's behavior. The flaw occurs during the processing of FTP responses that lack proper status code formatting, allowing attackers to inject script content that gets reflected back to users in error messages. This injection mechanism bypasses normal security controls because the application fails to properly escape or validate the content before rendering it in the user interface. The vulnerability's severity is amplified by its potential to be leveraged for privilege escalation, as demonstrated by the documented attack vector that enables root access through a sequence of web script operations. This sequence involves creating new FTP user accounts, effectively allowing attackers to establish persistent access to the system with elevated privileges. The attack chain demonstrates how a seemingly minor input validation flaw can be transformed into a critical system compromise.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with a pathway to achieve complete system compromise. The ability to create new FTP user accounts with elevated privileges essentially allows for persistent backdoor access to the system, making this vulnerability particularly dangerous in enterprise environments where FTP services are commonly deployed. From a cybersecurity perspective, this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and can be mapped to ATT&CK technique T1059.007 for scripting and T1078.002 for valid accounts, demonstrating the multi-stage nature of the attack. The vulnerability's exploitation requires minimal technical expertise and can be automated, making it attractive to both novice and experienced attackers. Organizations relying on SurgeFTP 2.3a1 are particularly at risk, as the default configuration may not include adequate protections against such reflected XSS attacks.
Mitigation strategies for CVE-2007-3769 must address both the immediate XSS vulnerability and the privilege escalation potential. Organizations should implement comprehensive input validation and sanitization measures to prevent script injection in all user-facing interfaces, particularly those handling external server responses. The application should properly escape all output before rendering it in the user interface, implementing proper HTML encoding and context-appropriate output filtering. Additionally, administrators should consider implementing network segmentation and access controls to limit exposure of the affected FTP servers to untrusted networks. Regular security updates and patches should be applied immediately upon availability, as this vulnerability has been known since 2007 and likely has multiple remediation options. The implementation of web application firewalls and content security policies can provide additional defense-in-depth layers. Security monitoring should include detection of malformed FTP responses and unusual user account creation patterns, as these activities may indicate exploitation attempts. Given the privilege escalation capability, organizations should also review and enforce least privilege principles for FTP service accounts and implement regular access reviews to detect unauthorized account creation.