CVE-2004-0346 in ProFTPD
Summary
by MITRE
Off-by-one buffer overflow in _xlate_ascii_write() in ProFTPD 1.2.7 through 1.2.9rc2p allows local users to gain privileges via a 1024 byte RETR command.
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Analysis
by VulDB Data Team • 06/27/2019
The vulnerability described in CVE-2004-0346 represents a critical buffer overflow condition within the ProFTPD server software that affects versions 1.2.7 through 1.2.9rc2p. This issue resides in the _xlate_ascii_write() function which handles the translation of ASCII data during file transfers, specifically when processing RETR commands. The flaw manifests as an off-by-one error that occurs when the server processes file retrieval operations, creating a condition where one additional byte can be written beyond the allocated buffer space. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, though the specific implementation creates a more nuanced privilege escalation scenario. The vulnerability is particularly dangerous because it operates within the context of a file transfer protocol server where local users already have access to the system, making the privilege escalation aspect more severe than typical remote exploitation scenarios.
The technical execution of this vulnerability requires a local user to issue a RETR command with a specifically crafted 1024 byte payload that triggers the buffer overflow condition. When the _xlate_ascii_write() function processes this command, the off-by-one error allows an attacker to overwrite adjacent memory locations, potentially corrupting the stack frame or control data structures. This memory corruption can be leveraged to execute arbitrary code with the privileges of the ProFTPD process, which typically runs with elevated permissions to manage file transfers and access system resources. The attack vector is classified as local privilege escalation under the ATT&CK framework, specifically mapping to the privilege escalation technique where adversaries leverage software vulnerabilities to gain elevated system privileges.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise when the target system runs ProFTPD with sufficient privileges. Since the vulnerability requires local access to exploit, it may be less immediately dangerous than remote exploits, but it provides a persistent foothold for attackers who already have user-level access to the system. The affected versions of ProFTPD were widely deployed in enterprise environments, making this vulnerability particularly impactful across multiple organizations. The buffer overflow condition can lead to denial of service, data corruption, or complete system compromise depending on how the memory corruption manifests. Organizations running these vulnerable versions face significant risk as attackers can use this vulnerability to establish persistent backdoors or escalate their access to full administrative privileges.
Mitigation strategies for CVE-2004-0346 involve immediate patching of the ProFTPD software to versions that address the buffer overflow condition in _xlate_ascii_write(). System administrators should also implement additional security controls such as restricting local user access to FTP services and monitoring for unusual RETR command patterns. The vulnerability highlights the importance of input validation and proper buffer management in server applications, particularly those handling user-supplied data. Organizations should conduct comprehensive vulnerability assessments to identify all instances of the affected ProFTPD versions and ensure proper patch management protocols are in place. Regular security audits and code reviews focusing on buffer handling and memory management practices can help prevent similar issues in other applications. The incident also underscores the necessity of maintaining up-to-date security patches and the risks associated with running outdated server software in production environments.