CVE-2001-0777 in OmniHTTPD
Summary
by MITRE
Omnicron OmniHTTPd 2.0.8 allows remote attackers to cause a denial of service (memory exhaustion) via a series of requests for PHP scripts.
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Analysis
by VulDB Data Team • 10/04/2025
The vulnerability identified as CVE-2001-0777 affects Omnicron OmniHTTPd version 2.0.8, a web server software that was widely used in enterprise environments during the early 2000s. This particular flaw represents a classic denial of service condition that can be exploited remotely by malicious actors to consume system resources and render the affected server unavailable to legitimate users. The vulnerability specifically targets the server's handling of PHP script requests, demonstrating a critical weakness in resource management and request processing logic that was prevalent in web server implementations of that era.
The technical flaw manifests when remote attackers submit a series of carefully crafted requests for PHP scripts to the vulnerable OmniHTTPd server. The server's inadequate memory management mechanisms fail to properly handle these consecutive requests, leading to progressive memory consumption that eventually exhausts available system resources. This memory exhaustion occurs because the server does not implement proper request queuing or resource limiting mechanisms, allowing malicious actors to continuously submit PHP requests without adequate resource checks or cleanup procedures. The vulnerability operates at the application layer and exploits the server's failure to properly manage memory allocation for PHP processing tasks, creating a condition where legitimate system resources become unavailable due to excessive consumption by malicious requests.
The operational impact of this vulnerability extends beyond simple service disruption, as it can effectively shut down critical web services and potentially impact business operations that depend on the affected server. Organizations running OmniHTTPd 2.0.8 may experience complete service outages, loss of productivity, and potential revenue impacts when this vulnerability is exploited. The remote nature of the attack means that adversaries can exploit the vulnerability from anywhere on the network without requiring physical access or local privileges, making it particularly dangerous for organizations with exposed web servers. This type of vulnerability aligns with CWE-400 which categorizes "Uncontrolled Resource Consumption" as a fundamental weakness in software design, and it maps to ATT&CK technique T1499.004 which covers "Endpoint Denial of Service" through resource exhaustion attacks.
Organizations should implement immediate mitigations including upgrading to a patched version of OmniHTTPd or applying the vendor-supplied security patches that address the memory management issues in the PHP request handling code. Network-level protections such as rate limiting and request filtering can provide temporary mitigation while permanent fixes are implemented. System administrators should also monitor for unusual traffic patterns and implement proper resource monitoring to detect potential exploitation attempts. The vulnerability serves as a reminder of the importance of proper resource management in web server implementations and highlights the need for comprehensive security testing of application-level components. Additionally, organizations should consider implementing web application firewalls and intrusion detection systems to help identify and block malicious request patterns that could lead to similar resource exhaustion conditions.