CVE-2018-0875 in .NET Core
Summary
by MITRE
.NET Core 1.0, .NET Core 1.1, NET Core 2.0 and PowerShell Core 6.0.0 allow a denial of Service vulnerability due to how specially crafted requests are handled, aka ".NET Core Denial of Service Vulnerability".
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Analysis
by VulDB Data Team • 02/21/2023
The vulnerability identified as CVE-2018-0875 represents a critical denial of service flaw affecting multiple Microsoft .NET Core and PowerShell Core implementations including versions 1.0, 1.1, 2.0, and PowerShell Core 6.0.0. This vulnerability stems from inadequate handling of specially crafted requests within the framework's request processing pipeline, creating a condition where maliciously constructed input can cause system resources to become exhausted or application processes to terminate unexpectedly. The flaw operates at the core networking and request parsing layers of these frameworks, making it particularly dangerous as it can be exploited across various application scenarios that rely on these technologies.
The technical implementation of this vulnerability involves the improper validation and processing of malformed or specially crafted HTTP requests and data payloads. When the affected .NET Core and PowerShell Core implementations encounter such requests, they fail to properly sanitize or reject the malicious input, leading to resource exhaustion through memory allocation issues, thread pool exhaustion, or infinite loop conditions within the request handling code. This behavior aligns with CWE-400, which categorizes improper resource management as a fundamental weakness in software design. The vulnerability specifically targets the framework's ability to process incoming requests efficiently, causing the application to become unresponsive or crash entirely.
The operational impact of this vulnerability extends beyond simple service disruption to encompass potential business continuity risks and system availability concerns. Attackers can exploit this weakness by sending carefully constructed requests that trigger resource exhaustion conditions, effectively rendering applications built on these frameworks unavailable to legitimate users. The vulnerability affects both server-side applications and client applications that utilize these frameworks, creating widespread potential for exploitation across enterprise environments. Organizations running web applications, APIs, or services that depend on .NET Core or PowerShell Core are particularly vulnerable, as these frameworks are commonly used in production environments. The attack surface is broad given the widespread adoption of these technologies in enterprise applications and cloud deployments.
Mitigation strategies for CVE-2018-0875 require immediate attention through patch management and configuration hardening measures. Microsoft released security updates for all affected versions that address the request processing logic and implement proper input validation mechanisms to prevent resource exhaustion conditions. Organizations should prioritize applying these patches across all affected systems and monitor for any signs of exploitation attempts. Network-level mitigations including rate limiting, request filtering, and intrusion detection systems can provide additional protection layers while patches are being deployed. The vulnerability also highlights the importance of implementing proper input validation at multiple layers of application architecture, aligning with ATT&CK technique T1499.001 which covers network denial of service attacks. Additionally, implementing proper monitoring and logging of request processing patterns can help detect anomalous behavior that might indicate exploitation attempts. Organizations should also consider implementing application firewalls and web application firewalls to filter out malicious requests before they reach the vulnerable framework components.