CVE-2000-0659 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 ID in a SOCKS4 CONNECT request.
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Analysis
by VulDB Data Team • 06/25/2021
The vulnerability described in CVE-2000-0659 represents a classic buffer overflow flaw within the AnalogX proxy server software version 4.04 and earlier. This issue specifically manifests when the proxy server processes SOCKS4 CONNECT requests containing excessively long user ID strings. The flaw resides in the server's inadequate input validation mechanisms, which fail to properly bounds-check the length of user identifiers submitted during the SOCKS4 protocol handshake process. When an attacker crafts a malicious SOCKS4 CONNECT request with an oversized user ID field, the proxy server attempts to store this data in a fixed-size buffer without proper boundary checks, leading to memory corruption.
The technical implementation of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The AnalogX proxy server's SOCKS4 implementation does not enforce maximum length constraints on the user ID field, which is typically 16 bytes in standard SOCKS4 protocol specifications. When an attacker submits a user ID exceeding the allocated buffer space, the overflow corrupts the stack or heap memory, potentially leading to application crashes or, in more sophisticated exploitation scenarios, arbitrary code execution. The vulnerability specifically affects the server's handling of the SOCKS4 protocol's user ID field, which is designed to carry authentication information for the connection request.
The operational impact of this buffer overflow vulnerability extends beyond simple denial of service, as it creates potential pathways for more serious security compromises within network infrastructure. Remote attackers can leverage this weakness to cause persistent service disruptions, effectively rendering the proxy server unavailable to legitimate users and potentially creating denial of service conditions that impact downstream network services. The vulnerability's remote exploitability means that attackers need not have physical access to the server or network segment, making it particularly dangerous in publicly accessible environments. Network administrators may experience cascading failures if the proxy server acts as a critical gateway component in their infrastructure, as service outages can propagate to multiple dependent systems and applications.
Mitigation strategies for CVE-2000-0659 should prioritize immediate software updates and patches from the vendor, as the AnalogX proxy server has been superseded by newer versions with proper input validation mechanisms. Network segmentation and access controls should be implemented to limit exposure of vulnerable proxy servers to untrusted networks, while implementing intrusion detection systems that can identify anomalous SOCKS4 traffic patterns. The principle of least privilege should be enforced by restricting the proxy server's network access and implementing firewall rules that limit the types of requests accepted. Additionally, regular security audits of legacy network infrastructure components should be conducted to identify and remediate similar buffer overflow vulnerabilities, as this class of weakness remains prevalent in older software systems and represents a fundamental security flaw that violates the security principle of input sanitization. Organizations should also consider implementing network monitoring solutions that can detect and alert on unusually long user ID fields in SOCKS4 requests, providing early warning of potential exploitation attempts.