CVE-2010-20122 in Xftp FTP Client
Summary
by MITRE • 08/22/2025
Xftp FTP Client version up to and including 3.0 (build 0238) contain a stack-based buffer overflow vulnerability triggered by a maliciously crafted PWD response from an FTP server. When the client connects to a server and receives an overly long directory string in response to the PWD command, the client fails to properly validate the length of the input before copying it into a fixed-size buffer. This results in memory corruption and allows remote attackers to execute arbitrary code on the client system.
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Analysis
by VulDB Data Team • 08/22/2025
The vulnerability identified as CVE-2010-20122 represents a critical stack-based buffer overflow flaw in Xftp FTP Client versions up to and including build 0238. This security weakness stems from inadequate input validation mechanisms within the client application's handling of FTP server responses, specifically when processing the PWD (Print Working Directory) command. The flaw creates a dangerous condition where the client application fails to enforce proper bounds checking on directory path strings received from remote FTP servers, leading to potential system compromise.
The technical implementation of this vulnerability occurs during the normal FTP communication process when the client establishes a connection to an FTP server and subsequently receives a response to the PWD command. When the server responds with an excessively long directory string that exceeds the predetermined buffer size allocated for storing directory paths, the client application's memory management fails to prevent the overflow condition. This buffer overflow manifests as a stack corruption scenario where the excessive data overflows into adjacent memory locations, potentially overwriting critical program execution elements including return addresses and function pointers.
From an operational perspective, this vulnerability presents a significant risk to users of the affected Xftp client versions as it enables remote code execution attacks without requiring any special privileges or user interaction beyond establishing a connection to a malicious FTP server. The attack vector is particularly concerning because it operates entirely within the normal FTP protocol communication flow, making it difficult to detect through standard network monitoring or intrusion detection systems. The vulnerability can be exploited by attackers who control an FTP server or have the ability to intercept and modify FTP traffic, allowing them to inject malicious code that executes with the privileges of the affected user.
The impact of this vulnerability aligns with CWE-121 stack-based buffer overflow classification, which specifically addresses buffer overflows occurring in stack memory regions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. This flaw also maps to ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would likely involve executing arbitrary commands through the compromised client application. The vulnerability's exploitation potential extends beyond simple code execution to include complete system compromise, data theft, and establishment of persistent backdoors within the victim environment.
Mitigation strategies for CVE-2010-20122 should prioritize immediate application of vendor patches or updates to Xftp client versions beyond build 0238, as this represents the most effective protection against the identified buffer overflow condition. Organizations should also implement network-level controls including firewall rules that restrict FTP server access to trusted sources and consider deploying network monitoring solutions capable of detecting anomalous PWD command responses. Additionally, security awareness training for users should emphasize the importance of connecting only to trusted FTP servers and avoiding automatic connections to unknown or unverified remote systems. System administrators should also consider implementing application whitelisting policies that restrict execution of untrusted FTP client applications and regularly audit FTP client usage patterns to identify potential exploitation attempts.