CVE-2002-0768 in Linux
Summary
by MITRE
Buffer overflow in lukemftp FTP client in SuSE 6.4 through 8.0, and possibly other operating systems, allows a malicious FTP server to execute arbitrary code via a long PASV command.
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Analysis
by VulDB Data Team • 06/08/2018
The vulnerability identified as CVE-2002-0768 represents a critical buffer overflow flaw in the lukemftp FTP client software that affected SuSE Linux distributions version 6.4 through 8.0, with potential impact extending to other operating systems. This vulnerability resides in the client's handling of the PASV command response from FTP servers, creating an exploitable condition that can be leveraged by malicious actors. The flaw specifically manifests when the client receives a malformed PASV response containing excessive data that exceeds the allocated buffer space, leading to memory corruption and potential code execution.
The technical implementation of this vulnerability follows the classic buffer overflow pattern where insufficient input validation occurs during processing of the PASV command response. When an FTP server sends a response to the client's PASV command that contains more data than the allocated buffer can accommodate, the excess data overflows into adjacent memory locations. This memory corruption can overwrite critical program execution elements such as return addresses, function pointers, or other control data structures, allowing an attacker to redirect program flow to execute malicious code injected into the overflowed buffer. The vulnerability is particularly dangerous because it operates at the application layer, requiring no special privileges from the attacker and can be exploited through normal network communication channels.
The operational impact of this vulnerability extends beyond simple privilege escalation or denial of service scenarios. An attacker who successfully exploits this buffer overflow can achieve full system compromise by executing arbitrary code with the privileges of the user running the lukemftp client. This represents a significant security risk in environments where users may connect to untrusted FTP servers, as the vulnerability can be triggered through routine file transfer operations without any special user interaction beyond initiating the connection. The attack vector is particularly concerning because FTP servers are commonly accessible and many users may not be aware of the security implications of connecting to potentially malicious servers. The vulnerability affects multiple versions of SuSE Linux, indicating it was likely present in the codebase for an extended period, providing attackers with multiple potential targets.
Mitigation strategies for this vulnerability should focus on both immediate remediation and long-term security hardening approaches. The primary solution involves updating the lukemftp client to a patched version that implements proper input validation and buffer size checking for PASV command responses. System administrators should also consider implementing network segmentation and access controls to limit exposure to potentially malicious FTP servers. Additionally, organizations should conduct security awareness training to educate users about the risks of connecting to untrusted FTP servers and the importance of verifying server authenticity before establishing connections. From a defensive perspective, this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and could be categorized under ATT&CK technique T1190 for exploitation through malicious file transfers. The vulnerability demonstrates the importance of proper input validation and memory management in client-side applications, particularly those handling network communications with untrusted entities.