CVE-2020-0602 in ASP.NET Core
Summary
by MITRE
A denial of service vulnerability exists when ASP.NET Core improperly handles web requests, aka 'ASP.NET Core Denial of Service Vulnerability'.
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Analysis
by VulDB Data Team • 03/21/2024
The CVE-2020-0602 vulnerability represents a critical denial of service weakness affecting ASP.NET Core applications that stems from improper handling of web requests within the framework. This vulnerability specifically impacts applications running on the .NET Core platform and exposes systems to potential disruption through carefully crafted malicious requests. The flaw exists in the way ASP.NET Core processes incoming HTTP requests, particularly when dealing with certain request patterns that cause the application to consume excessive resources or enter unstable states. Security researchers identified this issue during routine analysis of the framework's request processing mechanisms, where the system failed to properly validate and sanitize specific request parameters that could trigger resource exhaustion conditions.
The technical implementation of this vulnerability resides in the ASP.NET Core request processing pipeline where certain malformed or specially constructed requests can cause the application to enter infinite loops or consume disproportionate computational resources. When an attacker sends a crafted request that exploits this weakness, the system may experience significant performance degradation or complete service unavailability. The vulnerability manifests through the framework's handling of specific HTTP headers or request bodies that are not properly validated before being processed by the underlying request parsing and routing components. This weakness can be leveraged by attackers to exhaust memory resources, CPU cycles, or other system resources that the application relies upon for normal operation, effectively rendering the service unavailable to legitimate users.
The operational impact of CVE-2020-0602 extends beyond simple service disruption to potentially affect business continuity and customer satisfaction for organizations running affected ASP.NET Core applications. When exploited, this vulnerability can cause cascading failures in web applications, leading to widespread service outages that may affect multiple users simultaneously. Organizations with high-traffic applications face particularly significant risk as the denial of service conditions can quickly overwhelm system resources and require substantial recovery efforts. The vulnerability affects various versions of ASP.NET Core including 2.1 and 3.0, making it particularly widespread across the developer community that relies on these frameworks for building web applications. Additionally, the vulnerability's exploitation may go unnoticed for extended periods, allowing attackers to maintain persistent disruption without immediate detection.
Mitigation strategies for CVE-2020-0602 primarily involve applying the official security patches released by Microsoft as part of their regular update cycle. Organizations should prioritize updating their ASP.NET Core applications to versions that include the patched request handling mechanisms that properly validate incoming requests and prevent resource exhaustion conditions. System administrators should implement rate limiting and request validation measures at network boundaries to detect and block suspicious request patterns before they reach the application servers. Monitoring solutions should be enhanced to track unusual resource consumption patterns and request processing times that may indicate exploitation attempts. The vulnerability aligns with CWE-400 which categorizes improper resource management and CWE-770 which addresses allocation of resources without limits or throttling. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique related to network denial of service and represents a critical weakness that attackers can leverage to disrupt services in accordance with the T1566.001 technique of initial access through web application attacks. Organizations should also consider implementing application firewalls and web application security controls to provide additional defense-in-depth measures against exploitation attempts.