CVE-2010-20007 in Seagull FTP Client
Summary
by MITRE • 08/22/2025
Seagull FTP Client <= v3.3 Build 409 contains a stack-based buffer overflow vulnerability in its FTP directory listing parser. When the client connects to an FTP server and receives a crafted response to a LIST command containing an excessively long filename, the application fails to properly validate input length, resulting in a buffer overflow that overwrites the Structured Exception Handler (SEH). This may allow remote attackers to execute arbitrary code on the client system. This product line was discontinued and users were advised to use BlueZone Secure FTP instead, at the time of disclosure.
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Analysis
by VulDB Data Team • 08/22/2025
The vulnerability CVE-2010-20007 represents a critical stack-based buffer overflow in the Seagull FTP Client version 3.3 build 409 and earlier, demonstrating a fundamental flaw in input validation mechanisms within network protocol parsing. This vulnerability specifically affects the FTP directory listing parser component that processes responses from FTP servers, creating a dangerous condition where maliciously crafted server responses can trigger exploitable memory corruption. The flaw occurs when the client receives a LIST command response containing an excessively long filename that exceeds the allocated buffer size, causing the application to overwrite adjacent memory structures during the parsing process.
The technical exploitation of this vulnerability leverages the overwrite of the Structured Exception Handler (SEH) chain, a Windows-specific mechanism for handling exceptions and errors in application execution. When the buffer overflow occurs, it corrupts the SEH frame pointer that normally manages exception handling for the application, allowing an attacker to redirect execution flow to malicious code placed in the overflowed buffer. This technique aligns with common exploit methodologies documented in the ATT&CK framework under the T1059.007 sub-technique for command and scripting interpreter, where attackers leverage memory corruption vulnerabilities to achieve arbitrary code execution. The vulnerability is classified as CWE-121 stack-based buffer overflow, which represents one of the most prevalent and dangerous classes of software vulnerabilities.
The operational impact of this vulnerability extends beyond simple remote code execution, as it represents a complete compromise of the client system's security posture. Once successfully exploited, attackers gain the ability to execute arbitrary code with the privileges of the affected user, potentially leading to full system compromise, data exfiltration, or establishment of persistent backdoors. The vulnerability is particularly concerning because it requires no user interaction beyond connecting to a malicious FTP server, making it a prime candidate for automated exploitation. The attack surface is broad as any user who connects to an FTP server that can be compromised by an attacker is at risk, and the vulnerability affects all versions of the discontinued Seagull FTP Client product line.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security posture improvements. The primary recommendation involves immediate discontinuation of the affected Seagull FTP Client software and migration to supported alternatives such as BlueZone Secure FTP or other modern FTP clients that have been updated to address similar buffer overflow vulnerabilities. System administrators should implement network segmentation and firewall rules to limit exposure to potentially malicious FTP servers, while also ensuring that all systems have up-to-date security patches for the operating system and any remaining legacy software. Additionally, network monitoring should be enhanced to detect anomalous FTP traffic patterns that might indicate exploitation attempts, and regular security assessments should be conducted to identify other potentially vulnerable applications within the organization's attack surface. The vulnerability serves as a reminder of the critical importance of proper input validation and memory safety practices in network protocol implementations, as outlined in industry standards and best practices for secure software development.