CVE-2003-1209 in HTTP Daemon
Summary
by MITRE
The Post_Method function in Monkey HTTP Daemon before 0.6.2 allows remote attackers to cause a denial of service (crash) via a POST request without a Content-Type header.
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Analysis
by VulDB Data Team • 07/17/2025
The vulnerability identified as CVE-2003-1209 affects the Monkey HTTP Daemon version 0.6.1 and earlier, representing a critical denial of service flaw that can be exploited by remote attackers to crash the web server. This vulnerability specifically targets the Post_Method function within the HTTP daemon implementation, demonstrating a classic buffer overflow or improper input validation issue that occurs when processing HTTP POST requests. The flaw manifests when the server receives a POST request that lacks the mandatory Content-Type header field, creating a condition where the daemon fails to properly handle the malformed request and subsequently crashes.
The technical root cause of this vulnerability stems from inadequate input validation within the HTTP request processing pipeline of the Monkey daemon. When the Post_Method function encounters a POST request without a Content-Type header, it fails to properly validate or sanitize the incoming request parameters before attempting to process the request body. This represents a fundamental flaw in the request handling mechanism that can be classified under CWE-20, which covers improper input validation, and CWE-122, which addresses heap-based buffer overflow conditions. The absence of proper header validation creates an exploitable condition where an attacker can craft a malicious POST request that triggers an unhandled exception or memory corruption within the daemon's processing logic.
From an operational perspective, this vulnerability presents a significant risk to web server availability and system stability, as it allows remote attackers to perform denial of service attacks without requiring any authentication or privileged access. The impact extends beyond simple service disruption, as the daemon crash can result in complete service unavailability until manual intervention or automatic restart mechanisms are triggered. This vulnerability particularly affects environments where the Monkey HTTP Daemon serves as a critical web server component, potentially impacting web applications, API endpoints, and other HTTP-based services that rely on the daemon for request processing. The exploitability factor is high due to the simple nature of the attack vector, requiring only the ability to send HTTP POST requests to the affected server.
The attack pattern associated with CVE-2003-1209 aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion or application crashes. The vulnerability can be exploited using standard HTTP client tools or automated attack frameworks, making it accessible to attackers with minimal technical expertise. Organizations using the affected version of Monkey HTTP Daemon should prioritize immediate patching or mitigation strategies, as the vulnerability can be exploited in automated scanning campaigns targeting vulnerable web servers. The fix for this vulnerability involves implementing proper input validation within the Post_Method function to ensure that all required HTTP headers are present and properly formatted before proceeding with request processing, thereby preventing the daemon from crashing when encountering malformed POST requests.
Security practitioners should consider this vulnerability as part of broader HTTP server hardening efforts, particularly in environments where multiple web servers are deployed. The vulnerability demonstrates the importance of implementing comprehensive input validation across all HTTP request processing functions, as well as the need for proper error handling mechanisms that prevent crash conditions from occurring during abnormal request processing. Organizations should also implement monitoring and alerting for unexpected daemon crashes or restarts, as these events may indicate exploitation attempts. The remediation approach should include not only applying the official patch for Monkey HTTP Daemon version 0.6.2 but also conducting security reviews of other HTTP server implementations to identify similar input validation gaps that could present comparable risks.