CVE-1999-0235 in Webserver
Summary
by MITRE
buffer overflow in ncsa webserver (1.4.1 and below) gives remote access.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability identified as CVE-1999-0235 represents a critical buffer overflow flaw within the ncsa webserver version 1.4.1 and earlier releases. This issue stems from inadequate input validation mechanisms within the server's handling of HTTP requests, specifically when processing certain malformed or excessively long header fields. The buffer overflow occurs when the server attempts to store incoming data into a fixed-length buffer without proper bounds checking, allowing malicious actors to overwrite adjacent memory locations. This fundamental flaw creates a pathway for remote code execution, as attackers can manipulate the overflow to inject and subsequently execute arbitrary commands on the vulnerable system. The vulnerability is particularly dangerous because it affects the core web server functionality, potentially granting unauthorized users complete control over the affected machine.
The technical implementation of this buffer overflow vulnerability can be traced to the server's inadequate memory management practices and lack of proper input sanitization. When the ncsa webserver receives HTTP requests containing overly long header values, the application fails to validate the length of incoming data before copying it into internal buffers. This flaw aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows data to overwrite adjacent memory. The vulnerability operates at the application layer of the network stack, making it accessible through standard HTTP protocols without requiring special privileges or authentication. Attackers can exploit this weakness by crafting malicious HTTP requests with oversized header fields, causing the server to crash or, more critically, allowing them to inject shellcode that executes with the privileges of the web server process.
The operational impact of CVE-1999-0235 extends far beyond simple service disruption, as it fundamentally compromises the security posture of any system running vulnerable ncsa webserver versions. Remote attackers can leverage this vulnerability to gain full administrative control over the affected server, potentially using it as a foothold for further network infiltration. The compromise can result in data theft, service denial, or the establishment of persistent backdoors within the network infrastructure. Organizations running these outdated web server versions face significant risk of being exploited by automated scanning tools that continuously search for known vulnerabilities. The vulnerability also provides attackers with opportunities to perform lateral movement within networks, as compromised web servers often have access to internal resources that would otherwise be protected by network segmentation. This makes the impact particularly severe in enterprise environments where web servers serve as critical entry points for business applications.
Mitigation strategies for CVE-1999-0235 must prioritize immediate remediation through software updates and patches. The most effective approach involves upgrading to ncsa webserver version 1.4.2 or later, which includes proper input validation and buffer size controls that prevent the overflow condition. System administrators should also implement network-level protections such as firewalls and intrusion detection systems to monitor for suspicious HTTP traffic patterns that might indicate exploitation attempts. Additional defensive measures include disabling unnecessary web server features, implementing strict input validation at the network perimeter, and conducting regular vulnerability assessments to identify other potential attack vectors. The vulnerability demonstrates the critical importance of maintaining up-to-date software components and following secure coding practices that prevent buffer overflow conditions. Organizations should also consider implementing application-level firewalls and web application firewalls to provide additional protection layers against exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving remote code execution and privilege escalation, highlighting the need for comprehensive defensive strategies that address both network-level and application-level security controls.