CVE-2002-1930 in AN-HTTPd
Summary
by MITRE
Buffer overflow in AN HTTPd 1.38 through 1.4.1c allows remote attackers to execute arbitrary code via a SOCKS4 request with a long username.
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Analysis
by VulDB Data Team • 05/25/2025
The vulnerability identified as CVE-2002-1930 represents a critical buffer overflow flaw within AN HTTPd web server software version 1.38 through 1.4.1c. This security weakness specifically manifests when the server processes SOCKS4 requests, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized control over affected systems. The flaw stems from inadequate input validation mechanisms that fail to properly handle excessively long username fields within SOCKS4 protocol requests, leading to memory corruption that can be exploited for arbitrary code execution.
The technical implementation of this vulnerability involves the web server's handling of SOCKS4 protocol connections where user credentials are processed without sufficient bounds checking. When a malicious actor sends a specially crafted SOCKS4 request containing an overly long username string, the server's buffer management fails to properly terminate or truncate the input data, causing a stack buffer overflow condition. This type of vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which addresses out-of-bounds write operations. The overflow occurs because the software does not validate the length of the username field against the allocated buffer size, allowing attacker-controlled data to overwrite adjacent memory locations including return addresses and control flow information.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise and potential lateral movement within network environments. Attackers exploiting this flaw can gain full administrative privileges on affected servers, potentially using them as launch points for further attacks against internal network resources. The vulnerability affects organizations running legacy web server software that supports SOCKS4 proxy functionality, making it particularly dangerous in environments where older protocols are still in use. From an adversary perspective, this vulnerability aligns with ATT&CK technique T1210, which covers exploitation of remote services, and T1059, which covers command and scripting interpreter usage for persistence and execution.
Mitigation strategies for CVE-2002-1930 require immediate action including software updates to versions that properly address the buffer overflow condition, along with network-level restrictions that disable SOCKS4 protocol support where possible. Organizations should implement network segmentation to limit exposure of affected systems and deploy intrusion detection systems to monitor for suspicious SOCKS4 traffic patterns. Additionally, input validation should be strengthened at all protocol layers to prevent similar conditions from occurring in other software components. The vulnerability demonstrates the critical importance of proper memory management practices and input validation in network services, particularly those handling user-supplied data through proxy protocols. Security teams should conduct comprehensive vulnerability assessments to identify all instances of legacy software that may be susceptible to similar buffer overflow conditions, as this represents a common class of vulnerability that continues to affect systems in production environments.