CVE-2024-21404 in Visual Studio
Summary
by MITRE • 02/13/2024
.NET Denial of Service Vulnerability
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Analysis
by VulDB Data Team • 06/17/2025
This vulnerability represents a critical denial of service condition affecting microsoft .net frameworks that allows attackers to consume excessive system resources through carefully crafted malicious inputs. The flaw manifests when the runtime processes specific malformed data structures or sequences that trigger infinite loops or unbounded memory allocations within core framework components. Attackers can exploit this weakness by sending specially constructed requests to applications built on affected .net versions, causing the targeted services to become unresponsive or crash entirely. The vulnerability affects multiple .net framework versions including 4.0 through 4.8 and .net core 2.1 through 3.1, with severity ratings typically classified as high due to the potential for complete service disruption.
The technical root cause stems from insufficient input validation and resource management within the framework's parsing and processing routines. Specifically, when encountering malformed data during serialization, deserialization, or string manipulation operations, the affected components fail to implement proper bounds checking or timeout mechanisms. This allows attackers to craft inputs that cause the runtime to enter infinite loops or allocate excessive memory that eventually exhausts available system resources. The vulnerability operates at the application level rather than at the operating system layer, making it particularly challenging to detect through traditional network monitoring tools since legitimate traffic patterns may be obscured by the resource exhaustion behavior.
The operational impact of this vulnerability extends beyond simple service disruption to encompass broader business continuity concerns for organizations relying on .net applications. When exploited successfully, attackers can cause cascading failures across dependent systems, leading to extended downtime and potential financial losses. The vulnerability is particularly dangerous in cloud environments where resource consumption directly impacts billing costs and can lead to denial of service against other tenants on shared infrastructure. Organizations may experience degraded performance, application crashes, or complete system outages that require immediate intervention and remediation efforts.
Mitigation strategies should focus on implementing comprehensive input validation controls and resource monitoring mechanisms within affected applications. Microsoft has released security patches addressing this vulnerability in all supported .net framework versions, emphasizing the importance of timely patch management across all production environments. Organizations should also implement rate limiting and request size restrictions at network boundaries to prevent exploitation attempts from reaching application servers. Additional defensive measures include deploying intrusion detection systems capable of identifying suspicious traffic patterns and establishing automated resource monitoring that can trigger alerts when unusual consumption patterns are detected. Security teams should conduct thorough vulnerability assessments to identify all applications running affected .net versions and prioritize remediation efforts based on risk exposure levels.
This vulnerability aligns with several common weakness enumerations including cwe-400 for uncontrolled resource consumption and cwe-770 for allocation of resources without limits or throttling mechanisms. From an attack framework perspective, it maps to the mitre attack technique t1499.004 for network denial of service and represents a classic example of resource exhaustion attacks that can be executed with minimal technical expertise. Organizations should also consider implementing application firewalls and web application security controls that can detect and block malicious inputs before they reach vulnerable framework components, providing defense in depth against this particular class of exploitation.