CVE-2009-4103 in Robo-FTP
Summary
by MITRE
Buffer overflow in Robo-FTP 3.6.17, and possibly other versions, allows remote FTP servers to cause a denial of service and possibly execute arbitrary code via unspecified FTP server responses. NOTE: the provenance of this information is unknown; the details are obtained solely from third party information.
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Analysis
by VulDB Data Team • 01/23/2019
The vulnerability identified as CVE-2009-4103 represents a critical buffer overflow flaw in Robo-FTP version 3.6.17 and potentially other iterations of the software. This issue stems from inadequate input validation within the FTP client's response handling mechanism, where the application fails to properly sanitize or limit the size of data received from remote FTP servers. The buffer overflow occurs when the software processes FTP server responses that exceed predetermined memory allocation limits, creating a condition where maliciously crafted responses could overwrite adjacent memory locations. This vulnerability classifies under CWE-121 as a stack-based buffer overflow, which is particularly dangerous due to its potential for arbitrary code execution when exploited successfully.
The operational impact of this vulnerability extends beyond simple denial of service to encompass potential system compromise and unauthorized access. When a remote FTP server sends malformed responses that trigger the buffer overflow, the affected Robo-FTP client may crash or become unresponsive, leading to service disruption. However, the more severe implications arise when attackers can manipulate the overflow to inject and execute malicious code within the context of the running FTP client process. This exploitation vector aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution, as successful exploitation could allow adversaries to execute arbitrary commands on the compromised system. The vulnerability's remote nature means that attackers do not require physical access or local privileges to exploit this weakness, making it particularly concerning for automated attacks.
The technical implementation of this flaw demonstrates poor memory management practices within the Robo-FTP application's FTP protocol handling code. The software appears to use unsafe string handling functions that do not perform adequate bounds checking before copying data into fixed-size buffers. This pattern of vulnerability is consistent with classic buffer overflow exploits that have been documented in numerous security advisories over the years. The unspecified nature of the FTP server responses suggests that multiple types of malformed data could trigger the condition, making the vulnerability surface area broader than initially apparent. Security researchers should note that this vulnerability represents a classic example of how legacy software applications often contain unpatched buffer overflow conditions that remain exploitable for years after initial discovery. Organizations utilizing Robo-FTP or similar FTP client software should immediately implement mitigation strategies including software updates, network segmentation, and monitoring for suspicious FTP traffic patterns that could indicate exploitation attempts.