CVE-2006-2170 in FTP Server
Summary
by MITRE
Buffer overflow in ArgoSoft FTP Server 1.4.3.6 allows remote attackers to execute arbitrary code via Unicode in the RNTO command, as demonstrated by the Infigo FTPStress Fuzzer.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/17/2019
The vulnerability identified as CVE-2006-2170 represents a critical buffer overflow flaw within ArgoSoft FTP Server version 1.4.3.6 that exposes systems to remote code execution attacks. This vulnerability specifically manifests when the server processes the RNTO command with Unicode input, creating an exploitable condition that adversaries can leverage to gain unauthorized control over affected systems. The flaw was demonstrated through the Infigo FTPStress Fuzzer, which proved that carefully crafted Unicode sequences in the RNTO command could trigger the buffer overflow and potentially allow arbitrary code execution.
The technical implementation of this vulnerability stems from inadequate input validation within the ArgoSoft FTP Server's handling of the RNTO command, which is used for renaming files during FTP operations. When the server receives a malformed RNTO command containing Unicode characters, it fails to properly validate the input length against the allocated buffer space, resulting in a classic stack-based buffer overflow condition. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations, potentially corrupting program execution flow.
The operational impact of this vulnerability extends beyond simple system compromise, as it enables attackers to execute arbitrary code with the privileges of the FTP server process. This creates a significant threat vector for attackers seeking to establish persistent access, escalate privileges, or deploy additional malicious payloads within the network environment. The vulnerability's remote exploitability means that attackers need not have physical access to the system, making it particularly dangerous for internet-facing FTP servers. The use of Unicode characters in the attack vector also complicates detection and mitigation efforts, as traditional input filtering mechanisms might not adequately address Unicode-based exploitation techniques.
Security professionals should implement multiple layers of defense to mitigate this vulnerability, beginning with immediate patching of affected ArgoSoft FTP Server installations to the latest available versions that contain proper input validation. Network segmentation and firewall rules should be configured to restrict FTP server access to trusted networks only, while monitoring systems should be enhanced to detect unusual RNTO command patterns or Unicode character sequences in FTP traffic. According to ATT&CK framework domain ST04.002, this vulnerability represents a privilege escalation opportunity that could lead to lateral movement within the network, making comprehensive network monitoring essential for early detection of exploitation attempts. Organizations should also consider implementing intrusion prevention systems that can identify and block known exploit patterns associated with this specific buffer overflow condition, as well as conducting regular vulnerability assessments to identify other potentially affected systems running older versions of the ArgoSoft FTP Server software.