CVE-2005-4816 in ProFTPD
Summary
by MITRE
Buffer overflow in mod_radius in ProFTPD before 1.3.0rc2 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long password.
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Analysis
by VulDB Data Team • 07/20/2019
The vulnerability identified as CVE-2005-4816 represents a critical buffer overflow flaw within the mod_radius module of ProFTPD software versions prior to 1.3.0rc2. This issue resides in the authentication handling mechanism where the module fails to properly validate input length when processing user passwords during the radius authentication process. The buffer overflow occurs when a remote attacker submits an excessively long password string that exceeds the allocated buffer space, causing memory corruption that can lead to application instability and potential code execution.
The technical implementation of this vulnerability stems from inadequate bounds checking within the mod_radius module's password processing function. When ProFTPD receives an authentication request through the radius protocol, it passes the user-supplied password to the mod_radius module for validation. The flaw manifests when the password length surpasses the predefined buffer limit, typically resulting in stack corruption or heap overflow conditions. This type of vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios. The vulnerability exists at the intersection of improper input validation and memory management practices within the authentication module.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution, making it particularly dangerous for systems that rely on ProFTPD for file transfer services. Attackers can exploit this weakness to crash the ProFTPD service, rendering it unavailable to legitimate users and potentially gaining unauthorized access to system resources. The remote nature of the attack means that an attacker does not need physical access to the system or network credentials to exploit this vulnerability. According to ATT&CK framework, this vulnerability aligns with T1190, which covers exploitation of remote services, and T1059, which involves execution through command and scripting interpreter. The potential for arbitrary code execution makes this vulnerability particularly attractive to threat actors seeking persistent access to compromised systems.
Mitigation strategies for CVE-2005-4816 should prioritize immediate software updates to ProFTPD version 1.3.0rc2 or later, which contains the necessary patches to address the buffer overflow condition. System administrators should also implement network-level controls such as rate limiting and connection filtering to reduce the attack surface and prevent exploitation attempts. Additional defensive measures include disabling the mod_radius module if radius authentication is not required, implementing proper input validation at all network boundaries, and conducting regular security assessments of FTP services. The vulnerability demonstrates the importance of proper input validation and memory management practices in network services, particularly those handling authentication credentials. Organizations should also consider implementing intrusion detection systems to monitor for exploitation attempts and maintain comprehensive incident response procedures to address potential compromise. Regular security updates and vulnerability assessments remain crucial for maintaining defense in depth against similar buffer overflow vulnerabilities that may exist in other network services and applications.