CVE-2005-3031 in vxFtpSrv
Summary
by MITRE
Buffer overflow in vxFtpSrv 0.9.7 allows remote attackers to execute arbitrary code via a long USER name.
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Analysis
by VulDB Data Team • 07/12/2018
The vulnerability identified as CVE-2005-3031 represents a critical buffer overflow flaw in vxFtpSrv version 0.9.7, a lightweight ftp server implementation. This vulnerability resides within the authentication handling mechanism where the software fails to properly validate the length of user-provided credentials during the USER command processing. The flaw manifests when an attacker submits an excessively long username string that exceeds the allocated buffer space, causing memory corruption that can be exploited to execute arbitrary code on the affected system. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which occurs when data is written beyond the bounds of a fixed-length buffer allocated on the stack. This particular implementation flaw demonstrates poor input validation practices where the software does not enforce length restrictions on user-supplied data before processing it, creating a pathway for malicious exploitation. The attack vector is remote, meaning an unauthenticated attacker can leverage this vulnerability from outside the network perimeter without requiring any prior access credentials.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with full control over the affected ftp server process. When successfully exploited, the buffer overflow can overwrite critical memory locations including return addresses, function pointers, or other control data structures, allowing attackers to redirect program execution flow to malicious code injected into the buffer. This type of vulnerability aligns with ATT&CK technique T1190 which describes the exploitation of vulnerabilities in network services to gain remote access. The compromised server can then be used as a launching point for further attacks within the network infrastructure, potentially enabling lateral movement and privilege escalation. Additionally, attackers may leverage this vulnerability to establish persistent backdoors or to use the compromised server for malicious activities such as data exfiltration or as a proxy for other attacks. The vulnerability affects systems running vxFtpSrv 0.9.7 and potentially other versions with similar implementation flaws in their authentication handling code.
Mitigation strategies for CVE-2005-3031 should prioritize immediate patching of the affected software to address the buffer overflow condition. Organizations must ensure that all instances of vxFtpSrv 0.9.7 are updated to a patched version that implements proper input validation and buffer size checking. In environments where patching is not immediately feasible, network-level mitigations such as firewall rules can be implemented to restrict access to the ftp service to trusted networks only, reducing the attack surface. Additionally, implementing intrusion detection systems that monitor for suspicious USER command sequences can help detect potential exploitation attempts. The security community should also consider implementing application-level protections such as stack canaries or address space layout randomization to make exploitation more difficult. Regular security assessments of network services should include vulnerability scanning to identify similar buffer overflow conditions in other ftp implementations or network services. Organizations should also enforce principle of least privilege by running the ftp service with minimal required permissions and implementing proper logging to monitor authentication attempts that may indicate exploitation attempts. The vulnerability serves as a reminder of the importance of input validation and proper memory management in network service implementations, highlighting the need for adherence to secure coding practices and regular security updates.