CVE-2004-1136 in CuteFTP
Summary
by MITRE
Buffer overflow in CuteFTP Professional 6.0, and possibly other versions, allows remote FTP servers to cause a denial of service (application crash) via large replies to FTP commands.
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Analysis
by VulDB Data Team • 05/27/2019
The vulnerability identified as CVE-2004-1136 represents a critical buffer overflow flaw affecting CuteFTP Professional version 6.0 and potentially other iterations within the product line. This security weakness resides in the application's handling of FTP protocol responses from remote servers, specifically when processing large replies to FTP commands. The flaw manifests when the FTP client receives oversized responses that exceed the allocated buffer space, causing the application to crash and resulting in a denial of service condition. This vulnerability operates at the application layer of the network stack and directly impacts the stability and availability of the FTP client software.
The technical implementation of this buffer overflow stems from inadequate input validation and boundary checking within CuteFTP's FTP command processing routines. When remote FTP servers respond to client requests with oversized reply messages, the application fails to properly sanitize or truncate these responses before storing them in fixed-size buffers. This classic buffer overflow scenario occurs because the software does not perform sufficient length checks on incoming data, allowing malicious or malformed FTP server responses to overwrite adjacent memory locations. The vulnerability is particularly concerning as it can be triggered remotely without requiring authentication or special privileges, making it accessible to any attacker who can control or influence an FTP server that a victim might connect to.
From an operational perspective, this vulnerability creates significant availability risks for users of CuteFTP Professional 6.0. The denial of service condition effectively renders the application unusable until manually restarted, disrupting legitimate file transfer operations and potentially affecting business continuity. Attackers could exploit this weakness by setting up malicious FTP servers that respond with oversized data to trigger crashes, creating a persistent disruption for users who rely on the software for their FTP operations. The impact extends beyond individual users to organizational environments where multiple users might be affected simultaneously if they connect to compromised FTP servers or if the vulnerability is exploited in a man-in-the-middle scenario.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation that enables arbitrary code execution or denial of service. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique related to network denial of service, where adversaries leverage application-level flaws to disrupt services. The attack surface is particularly broad as it affects any user who connects to potentially malicious FTP servers, making it a significant concern for organizations that maintain open FTP connections or rely on third-party FTP services. Mitigation strategies should include immediate patching of affected versions, implementation of network segmentation to limit exposure to untrusted FTP servers, and consideration of alternative FTP clients that have been properly secured against such vulnerabilities. Organizations should also implement monitoring to detect unusual FTP server behavior that might indicate exploitation attempts.