CVE-2014-4643 in FTP
Summary
by MITRE
Multiple heap-based buffer overflows in the client in Core FTP LE 2.2 build 1798 allow remote FTP servers to cause a denial of service (application crash) and possibly execute arbitrary code via a long string in a reply to a (1) USER, (2) PASS, (3) PASV, (4) SYST, (5) PWD, or (6) CDUP command.
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Analysis
by VulDB Data Team • 12/15/2024
The vulnerability identified as CVE-2014-4643 represents a critical heap-based buffer overflow flaw in Core FTP LE version 2.2 build 1798 client software. This vulnerability exists within the client's handling of FTP server responses and affects multiple command sequences including USER, PASS, PASV, SYST, PWD, and CDUP commands. The flaw stems from inadequate input validation and bounds checking mechanisms within the client's response parsing logic, creating a scenario where malicious FTP servers can exploit the software's memory management to trigger unintended behavior.
The technical implementation of this vulnerability involves the client application's failure to properly validate the length of string data received from FTP servers during authentication and directory navigation operations. When a remote FTP server sends a specially crafted response containing an excessively long string in any of the mentioned command replies, the client's buffer management system attempts to copy this data into a pre-allocated heap buffer without sufficient bounds checking. This results in memory corruption that manifests as application crashes or potentially allows for arbitrary code execution through controlled memory overwrite techniques.
From an operational perspective, this vulnerability creates significant risk for users who may encounter malicious FTP servers or compromised systems that could exploit this flaw. The denial of service impact means that legitimate users could experience application instability and service disruption when connecting to vulnerable FTP servers. The potential for arbitrary code execution elevates this to a critical security concern, as attackers could potentially gain control of the victim's system and execute malicious payloads with the privileges of the affected user.
The vulnerability aligns with CWE-121 heap-based buffer overflow classification and maps to ATT&CK technique T1203 (Exploitation for Client Execution) within the adversary tactics framework. This mapping reflects how attackers can leverage client-side vulnerabilities to execute malicious code on target systems. The exploitability of this vulnerability is enhanced by the fact that it requires minimal user interaction beyond establishing an FTP connection, making it particularly dangerous in environments where users may connect to untrusted FTP servers. The impact extends beyond immediate system compromise to include potential data exfiltration, persistence mechanisms, and further lateral movement within compromised networks.
Mitigation strategies should focus on immediate patching of the Core FTP LE client to the latest version that addresses this vulnerability. Network administrators should implement FTP server filtering and monitoring to detect and block suspicious responses that might contain oversized data strings. Additionally, users should be educated about the risks of connecting to untrusted FTP servers and the importance of keeping client software updated. The vulnerability highlights the critical importance of input validation and proper memory management in client applications, particularly those handling network communications where external data sources cannot be trusted. Organizations should also consider implementing network segmentation and access controls to limit exposure to potentially malicious FTP servers in their environments.