CVE-2018-0787 in ASP.NET Core
Summary
by MITRE
ASP.NET Core 1.0. 1.1, and 2.0 allow an elevation of privilege vulnerability due to how web applications that are created from templates validate web requests, aka "ASP.NET Core Elevation Of Privilege Vulnerability".
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Analysis
by VulDB Data Team • 02/21/2023
The CVE-2018-0787 vulnerability represents a critical elevation of privilege flaw affecting ASP.NET Core versions 1.0, 1.1, and 2.0. This vulnerability stems from improper validation of web requests within applications generated from default templates, creating a pathway for malicious actors to escalate their privileges within the application environment. The flaw specifically impacts the request validation mechanisms that are fundamental to web application security, particularly in how these frameworks handle incoming HTTP requests and their associated data. The vulnerability exists at the core of ASP.NET Core's request processing pipeline where template-based applications fail to adequately sanitize or validate incoming request parameters, potentially allowing attackers to manipulate request data to gain unauthorized access to restricted resources or functionality.
The technical implementation of this vulnerability lies in the inadequate request validation logic within the ASP.NET Core framework's template generation system. When developers create new applications using the default templates, the framework automatically includes certain request handling components that do not properly validate the integrity of incoming requests. This allows attackers to craft malicious requests that bypass normal validation checks, potentially enabling them to execute arbitrary code or access protected application resources. The vulnerability specifically manifests when applications process request data that contains specially crafted parameters designed to exploit the weak validation mechanisms. According to CWE classification, this vulnerability maps to CWE-20: Improper Input Validation, which encompasses issues where applications fail to properly validate input data, leading to various security consequences including privilege escalation. The flaw demonstrates how template-based development environments can introduce security weaknesses that persist across multiple applications without explicit developer intervention.
The operational impact of CVE-2018-0787 extends beyond simple privilege escalation to potentially enable full application compromise and data exfiltration. Attackers leveraging this vulnerability can gain unauthorized access to application resources, potentially leading to complete system compromise if the application has elevated privileges or access to sensitive data stores. The vulnerability affects organizations running affected ASP.NET Core versions across their web applications, creating a significant risk surface that could be exploited by threat actors. In enterprise environments, this vulnerability could enable attackers to move laterally within networks, access confidential data, or establish persistent access points through compromised web applications. The impact is particularly severe because the vulnerability affects applications created from standard templates, meaning that many organizations may unknowingly deploy vulnerable applications without implementing additional security controls. From an ATT&CK framework perspective, this vulnerability aligns with techniques such as T1068: Exploitation for Privilege Escalation and T1190: Exploit Public-Facing Application, demonstrating how attackers can leverage application vulnerabilities to gain elevated system access.
Mitigation strategies for CVE-2018-0787 require immediate action from affected organizations to upgrade their ASP.NET Core framework versions to patched releases. Microsoft released updates addressing this vulnerability in subsequent releases, making it imperative for organizations to implement these patches promptly. Additionally, organizations should conduct comprehensive vulnerability assessments of their web applications to identify any instances where the vulnerable template-based applications may be deployed. Security teams should implement additional request validation controls beyond the default framework mechanisms, including custom validation logic and input sanitization measures. Network segmentation and application firewalls can provide additional layers of protection by monitoring and filtering suspicious request patterns. Organizations should also establish security monitoring procedures specifically designed to detect exploitation attempts of this vulnerability, including monitoring for unusual request patterns or attempts to access restricted application resources. Regular security testing and code reviews should be implemented to ensure that applications built from templates maintain proper security controls and do not inherit the vulnerable validation mechanisms. The remediation process must include comprehensive testing to ensure that patches do not introduce regressions in application functionality while maintaining the security improvements.