CVE-2011-3976 in ScriptFTP
Summary
by MITRE
Stack-based buffer overflow in AmmSoft ScriptFTP 3.3 allows remote FTP servers to execute arbitrary code via a long filename in a response to a LIST command, as demonstrated using (1) GETLIST or (2) GETFILE in a ScriptFTP script.
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Analysis
by VulDB Data Team • 01/05/2025
The vulnerability identified as CVE-2011-3976 represents a critical stack-based buffer overflow flaw in AmmSoft ScriptFTP version 3.3 that exposes remote FTP servers to potential code execution attacks. This vulnerability specifically targets the client-side application's handling of file listings during FTP operations, creating a dangerous condition where malicious FTP servers can exploit the software's insufficient input validation mechanisms. The flaw manifests when the ScriptFTP client processes responses to LIST commands, particularly in scenarios involving GETLIST or GETFILE operations within script files, allowing attackers to craft specially malformed responses that trigger the buffer overflow condition.
The technical implementation of this vulnerability stems from inadequate bounds checking within the ScriptFTP application's FTP response parsing logic. When the client receives a LIST command response containing an excessively long filename, the application fails to validate the length of the incoming data before copying it into a fixed-size stack buffer. This classic buffer overflow scenario occurs because the software does not implement proper input sanitization or length verification before storing the filename data, directly violating established security principles for memory management and input validation. The vulnerability operates at the application layer of the network stack, specifically within the FTP client's file listing processing functionality, making it particularly dangerous as it can be exploited through legitimate network communications.
The operational impact of this vulnerability extends beyond simple code execution capabilities to encompass potential system compromise and unauthorized access to sensitive data. An attacker controlling a malicious FTP server can leverage this vulnerability to inject and execute arbitrary code on systems running vulnerable versions of ScriptFTP, potentially gaining full control over the affected machine. The attack vector is particularly insidious because it requires no special privileges or complex exploitation techniques beyond the ability to control an FTP server that communicates with the target system. This makes the vulnerability particularly dangerous in environments where users frequently connect to external FTP servers or where automated scripts might access untrusted file listing data, creating multiple potential attack surfaces.
Mitigation strategies for CVE-2011-3976 should prioritize immediate software updates and patches from the vendor, as the vulnerability represents a well-documented flaw that has likely been addressed in subsequent releases. Organizations should implement network segmentation and access controls to limit exposure to untrusted FTP servers, while also monitoring for suspicious FTP activity that might indicate exploitation attempts. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which is classified as a high-risk weakness in the Common Weakness Enumeration catalog, and corresponds to attack techniques in the MITRE ATT&CK framework under T1059 Command and Scripting Interpreter and T1071.1003 Application Layer Protocol. System administrators should also consider implementing network-based intrusion detection systems to monitor for patterns consistent with this specific attack vector, while conducting thorough vulnerability assessments to identify other potentially affected applications that may exhibit similar buffer overflow characteristics in their FTP handling code.