CVE-2004-0276 in HTTP Daemon
Summary
by MITRE
The get_real_string function in Monkey HTTP Daemon (monkeyd) 0.8.1 and earlier allows remote attackers to cause a denial of service (crash) via an HTTP request with a sequence of "%" characters and a missing Host field.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/02/2025
The CVE-2004-0276 vulnerability affects the Monkey HTTP Daemon version 0.8.1 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 get_real_string function within the daemon's codebase, demonstrating a fundamental flaw in how the software handles malformed HTTP requests. The vulnerability arises from insufficient input validation and error handling mechanisms that fail to properly process malformed request sequences, creating a condition where the daemon becomes unstable and crashes under specific attack conditions.
The technical exploitation of this vulnerability occurs when an attacker crafts an HTTP request containing a sequence of "%" characters combined with a missing Host field in the request headers. This particular combination triggers a buffer manipulation issue within the get_real_string function, where the daemon attempts to process the malformed input without proper bounds checking or validation. The flaw essentially creates a situation where the function cannot properly handle the encoded characters in the context of a missing Host header, leading to memory corruption or stack overflow conditions that result in the daemon crashing. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, where insufficient bounds checking allows attackers to manipulate memory locations and cause system instability.
From an operational perspective, this vulnerability presents a significant risk to web server availability and system reliability. The remote nature of the attack means that any system running the affected version of Monkey HTTP Daemon is potentially vulnerable to being crashed by an unauthenticated attacker who can simply send a crafted HTTP request. The impact extends beyond simple service disruption as the daemon crash can lead to complete unavailability of the web server, potentially affecting business operations and user access to web applications. Organizations relying on this web server software face the risk of prolonged downtime and potential revenue loss due to the denial of service condition. The vulnerability also demonstrates poor input validation practices that could potentially be exploited further if similar flaws exist elsewhere in the codebase, making it a critical security concern for system administrators.
The mitigation strategies for CVE-2004-0276 primarily focus on immediate software updates and configuration hardening. The most effective solution involves upgrading to a patched version of Monkey HTTP Daemon that addresses the buffer handling issue in the get_real_string function. System administrators should also implement network-level protections such as intrusion detection systems and web application firewalls that can detect and block malformed HTTP requests before they reach the vulnerable daemon. Additionally, configuring the daemon to enforce stricter header validation and implementing rate limiting mechanisms can help reduce the effectiveness of such attacks. The vulnerability also highlights the importance of proper input sanitization and bounds checking in web server implementations, aligning with ATT&CK technique T1499.004 for network denial of service attacks and emphasizing the need for robust defensive coding practices. Organizations should also consider implementing monitoring solutions that can detect unusual crash patterns or service disruptions that might indicate exploitation attempts, providing early warning capabilities for potential attacks.