CVE-1999-0267 in httpd
Summary
by MITRE
buffer overflow in ncsa http daemon v1.3 allows remote command execution.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/26/2025
The vulnerability described in CVE-1999-0267 represents a critical buffer overflow flaw within the ncsa http daemon version 1.3, a widely used web server implementation that was prevalent during the late 1990s. This particular vulnerability resides in the server's handling of HTTP requests, specifically when processing certain malformed input parameters that exceed the allocated buffer space. The flaw manifests when the daemon receives a specially crafted request that triggers an unchecked buffer overflow condition, allowing an attacker to overwrite adjacent memory locations and potentially execute arbitrary code on the target system. This type of vulnerability falls under the common weakness enumeration CWE-121, which categorizes buffer overflow conditions that occur when insufficient bounds checking is performed during memory operations.
The technical exploitation of this vulnerability leverages the fundamental weakness in the daemon's input validation mechanisms, where HTTP request parameters are not properly sanitized before being processed by the server's internal functions. When the daemon attempts to store incoming data into a fixed-size buffer without adequate length checks, it becomes susceptible to memory corruption that can be manipulated by remote attackers. The overflow typically occurs during string operations or parameter parsing, where the server's internal buffer handling routines fail to account for the possibility of input data exceeding predetermined limits. This vulnerability directly aligns with ATT&CK technique T1203, which describes the exploitation of input validation vulnerabilities to gain unauthorized access and execute commands remotely. The attack vector requires only network connectivity to the affected web server, making it particularly dangerous as it can be exploited from anywhere on the internet without requiring physical access or prior authentication.
The operational impact of this vulnerability extends far beyond simple denial of service conditions, as successful exploitation can result in complete system compromise and unauthorized command execution. An attacker who successfully exploits this buffer overflow can gain root privileges on the affected server, allowing them to install backdoors, modify system files, steal sensitive data, or use the compromised system as a launch point for further attacks against the internal network. The ncsa http daemon was commonly used in enterprise environments during the late 1990s, making this vulnerability particularly dangerous as it could affect numerous critical systems. The remote nature of the exploit means that attackers can operate from anywhere in the world without requiring physical access to the target infrastructure. The vulnerability's severity is compounded by the fact that it was discovered and disclosed during a period when many organizations had limited security awareness and patch management processes in place. Organizations running this vulnerable software faced significant risk of unauthorized access and potential data breaches, as the vulnerability could be exploited automatically by malicious actors using readily available exploitation tools. The lack of proper input validation in the daemon's codebase demonstrates a critical gap in secure coding practices that was prevalent in software development during this era, highlighting the need for comprehensive security testing and code review processes. Modern security frameworks emphasize the importance of implementing proper bounds checking and input validation as fundamental defensive measures against such buffer overflow vulnerabilities, which are classified under the broader category of memory safety issues that continue to plague software systems today.