CVE-2000-0359 in thttpd
Summary
by MITRE
Buffer overflow in Trivial HTTP (THTTPd) allows remote attackers to cause a denial of service or execute arbitrary commands via a long If-Modified-Since header.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/16/2025
The vulnerability identified as CVE-2000-0359 represents a critical buffer overflow flaw within Trivial HTTP daemon version 2.28 and earlier versions. This web server implementation, designed for simplicity and minimal resource usage, contains a fundamental security weakness that can be exploited remotely to compromise system integrity. The vulnerability specifically manifests when the server processes HTTP requests containing excessively long If-Modified-Since header values, which are typically used by clients to request resources only if they have been modified since a specified date.
The technical implementation of this buffer overflow stems from inadequate input validation within the HTTP header processing routine. When THTTPd receives an HTTP request with an If-Modified-Since header exceeding the allocated buffer space, the server fails to properly terminate or truncate the input data before processing. This condition allows attackers to overwrite adjacent memory locations, potentially corrupting program execution flow and creating opportunities for arbitrary code execution. The vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and demonstrates how improper boundary checking can lead to memory corruption. The flaw occurs because the server does not enforce strict limits on header length before copying data into fixed-size buffers, creating an exploitable condition that can be triggered through HTTP request manipulation.
The operational impact of this vulnerability extends beyond simple denial of service to encompass potential complete system compromise. Remote attackers can leverage this weakness to execute arbitrary commands on the affected system with the privileges of the web server process, which typically runs with limited but potentially elevated permissions. The consequences include unauthorized access to server resources, data exfiltration, and potential lateral movement within network environments where the vulnerable server operates. This vulnerability aligns with ATT&CK technique T1190, which covers exploiting vulnerabilities in web applications, and represents a classic example of how web server implementations can become attack vectors for privilege escalation and persistent access. The DoS aspect of this vulnerability can also be weaponized to disrupt legitimate service availability, creating a dual threat that impacts both confidentiality and availability aspects of the system security posture.
Mitigation strategies for CVE-2000-0359 require immediate action to address the root cause through software updates and configuration hardening. Organizations should prioritize upgrading to THTTPd version 2.29 or later, which includes proper input validation and buffer size enforcement for HTTP headers. Additionally, implementing network-level protections such as intrusion detection systems can help detect and block malformed HTTP requests containing excessively long headers. The configuration of web servers should include explicit header length limits and input sanitization measures to prevent similar vulnerabilities from manifesting in other components. Security monitoring should focus on detecting unusual HTTP request patterns, particularly those with headers exceeding normal length parameters. System administrators should also consider implementing application firewalls and web application firewalls to provide additional layers of protection against malformed requests that could exploit similar buffer overflow conditions. Regular security assessments and vulnerability scanning should be conducted to identify other potential buffer overflow vulnerabilities within web server implementations and related network services.