CVE-2014-0253 in .NET Framework
Summary
by MITRE
Microsoft .NET Framework 1.1 SP1, 2.0 SP2, 3.5, 3.5.1, 4, 4.5, and 4.5.1 does not properly determine TCP connection states, which allows remote attackers to cause a denial of service (ASP.NET daemon hang) via crafted HTTP requests that trigger persistent resource consumption for a (1) stale or (2) closed connection, as exploited in the wild in February 2014, aka "POST Request DoS Vulnerability."
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Analysis
by VulDB Data Team • 01/08/2025
The CVE-2014-0253 vulnerability represents a critical denial of service flaw in Microsoft .NET Framework versions spanning from 1.1 SP1 through 4.5.1, exploiting a fundamental weakness in TCP connection state management within the ASP.NET daemon process. This vulnerability operates through a sophisticated mechanism where malicious actors craft specially designed HTTP requests that manipulate connection states in ways that cause the framework to enter an inconsistent state, ultimately leading to daemon hanging and complete service unavailability. The flaw specifically targets the framework's inability to properly handle stale or closed connections, creating a persistent resource consumption scenario that can be exploited remotely without authentication.
The technical exploitation of this vulnerability leverages the .NET Framework's TCP connection handling logic, which fails to correctly identify and dispose of connections that have already been closed or become stale. When an attacker sends crafted HTTP requests that trigger the framework to maintain references to these invalid connection states, the ASP.NET daemon begins to consume excessive system resources as it attempts to process these malformed requests. This condition creates a resource exhaustion scenario where the daemon becomes unresponsive, effectively causing a denial of service that impacts all applications running on the affected .NET Framework versions. The vulnerability's exploitation pattern involves sending POST requests that maintain connection state indefinitely, forcing the system to keep processing these connections even after they should have been terminated.
The operational impact of CVE-2014-0253 is severe and far-reaching, particularly given its exploitation in the wild during February 2014. Organizations running web applications based on affected .NET Framework versions experienced complete service outages as the ASP.NET daemon would hang indefinitely, requiring manual intervention to restore normal operations. This vulnerability particularly affected high-traffic web servers and applications that handle numerous concurrent connections, as the resource consumption pattern could quickly overwhelm system resources and cause cascading failures. The attack vector's remote nature means that any system running the vulnerable .NET Framework components could be compromised, regardless of network segmentation or firewall configurations, making it a particularly dangerous vulnerability for enterprise environments.
This vulnerability maps directly to CWE-400, which classifies it as an "Uncontrolled Resource Consumption" weakness, and aligns with ATT&CK technique T1499.004 for "Endpoint Denial of Service" within the adversary tactics framework. The attack pattern demonstrates a classic resource exhaustion exploit that can be automated, making it particularly dangerous for organizations with insufficient monitoring and alerting capabilities. Security professionals should note that the vulnerability's impact extends beyond simple service disruption to potentially affect business continuity and customer experience, particularly in mission-critical applications where availability is paramount.
Organizations should implement immediate mitigations including applying Microsoft security patches and updates to all affected .NET Framework versions, implementing connection timeout configurations, and establishing robust monitoring for unusual connection patterns that might indicate exploitation attempts. Network-level mitigations such as implementing rate limiting and connection tracking can help reduce the impact of exploitation attempts, while application-level protections including proper connection management and resource cleanup procedures should be implemented to prevent similar vulnerabilities in custom code. The vulnerability serves as a reminder of the critical importance of proper state management in networked applications and the potential for seemingly minor flaws to cause catastrophic system failures.