CVE-2011-5164 in AbsoluteFTP
Summary
by MITRE
Stack-based buffer overflow in VanDyke Software AbsoluteFTP 1.9.6 through 2.2.10 allows remote FTP servers to execute arbitrary code via a crafted file name in a LIST command response.
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Analysis
by VulDB Data Team • 01/05/2025
The vulnerability identified as CVE-2011-5164 represents a critical stack-based buffer overflow flaw within VanDyke Software AbsoluteFTP versions 1.9.6 through 2.2.10. This vulnerability specifically affects the FTP client component when processing LIST command responses from remote FTP servers, creating a dangerous execution path that can be exploited by malicious actors. The flaw exists in the client-side parsing logic where the software fails to properly validate or limit the length of file names contained within FTP directory listings, allowing attackers to craft malicious responses that exceed the allocated buffer space on the client system. This vulnerability falls under the CWE-121 category of stack-based buffer overflow, which is classified as a fundamental memory safety issue that has been consistently identified as one of the most dangerous classes of software vulnerabilities in cybersecurity.
The technical exploitation of this vulnerability occurs when an attacker controls a remote FTP server that the vulnerable client connects to and sends a specially crafted LIST command response containing an excessively long file name. When the AbsoluteFTP client processes this response, the parsing function attempts to copy the malformed file name into a fixed-size stack buffer without proper bounds checking. This buffer overflow can overwrite adjacent memory locations including return addresses and control data, potentially allowing an attacker to redirect program execution flow and execute arbitrary code with the privileges of the affected user. The attack vector is particularly concerning because it requires no local access or authentication, making it a remote code execution vulnerability that can be exploited over the network.
The operational impact of CVE-2011-5164 extends beyond simple code execution, as it represents a significant threat to system integrity and confidentiality. When successfully exploited, attackers can gain complete control over the victim's system, potentially leading to data theft, system compromise, or use as a foothold for further attacks within a network. The vulnerability affects a wide range of systems that utilize the AbsoluteFTP client, particularly those in enterprise environments where FTP clients are commonly used for file transfers and system administration tasks. Organizations that have legacy systems or older versions of the software remain particularly vulnerable, as the patching process may be delayed due to compatibility concerns or lack of maintenance support for older software versions.
Mitigation strategies for this vulnerability should focus on immediate remediation through software updates and patches provided by VanDyke Software, as well as network-level defenses. Organizations should prioritize updating to versions of AbsoluteFTP that contain the fix for this vulnerability, typically those beyond version 2.2.10. Network segmentation and firewall rules can help limit exposure by restricting access to FTP servers from untrusted networks. Additionally, implementing network monitoring to detect suspicious LIST command responses and file name patterns can provide early warning of potential exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving remote code execution and privilege escalation, with potential use in lateral movement within compromised networks. The vulnerability also aligns with defensive techniques focused on input validation and memory safety practices that should be implemented across all FTP client implementations to prevent similar issues from occurring in the future.