CVE-2000-0656 in AnalogX
Summary
by MITRE
Buffer overflow in AnalogX proxy server 4.04 and earlier allows remote attackers to cause a denial of service via a long USER command in the FTP protocol.
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Analysis
by VulDB Data Team • 02/01/2025
The vulnerability identified as CVE-2000-0656 represents a critical buffer overflow flaw within AnalogX proxy server version 4.04 and earlier implementations. This security weakness specifically manifests during the processing of FTP protocol commands, where the proxy server fails to properly validate the length of user-supplied input data. The flaw occurs when the server receives a USER command containing an excessively long string of characters, causing the application to overwrite adjacent memory segments beyond the allocated buffer boundaries. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions that can lead to arbitrary code execution or system instability. The AnalogX proxy server operates as a network filtering mechanism that processes incoming FTP requests, making it a prime target for exploitation by malicious actors seeking to disrupt network services.
The technical implementation of this vulnerability stems from inadequate input validation procedures within the FTP protocol handler of the AnalogX proxy software. When a remote attacker submits a USER command with a string length exceeding the predetermined buffer capacity, the server's memory management routines fail to enforce proper bounds checking. This results in memory corruption that can manifest in various ways including application crashes, system instability, or in more severe cases, potential exploitation for privilege escalation. The buffer overflow occurs at the application layer where the server processes authentication requests, making it particularly dangerous as it can be triggered without requiring authentication credentials. The vulnerability demonstrates a classic example of improper input handling that violates fundamental security principles outlined in the OWASP Top Ten and aligns with ATT&CK technique T1499.004 related to network denial of service attacks. The specific nature of the flaw suggests that the software uses a fixed-size buffer for storing user names without implementing proper bounds checking or dynamic memory allocation strategies.
The operational impact of CVE-2000-0656 extends beyond simple service disruption to potentially compromise the entire network infrastructure relying on the affected proxy server. Remote attackers can exploit this vulnerability to initiate denial of service attacks that render the proxy server non-functional, thereby blocking legitimate FTP traffic and disrupting business operations. The attack vector is particularly concerning as it requires no authentication credentials, making it accessible to any external party with network connectivity to the affected system. In environments where the AnalogX proxy server serves as a critical gateway for FTP communications, this vulnerability could result in significant downtime and potential data access restrictions. The flaw's exploitation capabilities align with the ATT&CK framework's T1498 technique for network denial of service, where adversaries leverage system weaknesses to prevent legitimate users from accessing network resources. Organizations utilizing this proxy server version face substantial risk of service interruption that could cascade into broader network availability issues, particularly in scenarios where multiple services depend on the proxy for FTP protocol handling.
Mitigation strategies for CVE-2000-0656 should prioritize immediate software updates to versions that address the buffer overflow vulnerability. System administrators must ensure that all AnalogX proxy servers are upgraded to versions 4.05 or later, where the buffer handling routines have been properly implemented with bounds checking mechanisms. Additionally, network segmentation and access control measures should be enforced to limit exposure of vulnerable systems to untrusted networks. Implementing proper input validation at the network perimeter through firewalls and intrusion prevention systems can help detect and block malformed USER commands before they reach the vulnerable proxy server. Security monitoring should include detection of unusual FTP protocol patterns that might indicate exploitation attempts, with logging mechanisms configured to capture command length variations. The vulnerability underscores the importance of maintaining up-to-date software versions and implementing defense-in-depth strategies that protect against both known and unknown threats. Organizations should also consider implementing network-based intrusion detection systems that can identify suspicious FTP protocol behavior and automatically alert security teams to potential exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify other potentially vulnerable components within the network infrastructure that may share similar buffer overflow characteristics.