CVE-2020-0646 in .NET Framework
Summary
by MITRE
A remote code execution vulnerability exists when the Microsoft .NET Framework fails to validate input properly, aka '.NET Framework Remote Code Execution Injection Vulnerability'.
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Analysis
by VulDB Data Team • 04/06/2025
The CVE-2020-0646 vulnerability represents a critical remote code execution flaw within Microsoft .NET Framework implementations that stems from inadequate input validation mechanisms. This vulnerability specifically affects systems running affected versions of the .NET Framework, creating a pathway for malicious actors to execute arbitrary code on targeted systems. The flaw manifests when the framework fails to properly sanitize or validate user-supplied input data, allowing attackers to craft malicious payloads that exploit this validation gap. Security researchers have identified this issue as a significant concern due to its remote exploitation capabilities and the widespread use of .NET Framework across enterprise environments.
The technical nature of this vulnerability aligns with CWE-20, which describes improper input validation, and specifically relates to injection flaws that occur when untrusted data is sent to an interpreter as part of a command or query. The vulnerability exploits the framework's insufficient validation of serialized data, particularly affecting the deserialization process where objects are reconstructed from serialized formats. Attackers can leverage this weakness by crafting specially formatted input that, when processed by the vulnerable .NET Framework, triggers arbitrary code execution. The flaw particularly impacts applications that utilize the System.Runtime.Serialization namespace and related serialization mechanisms, making it applicable to a broad range of enterprise applications that depend on .NET Framework functionality.
From an operational perspective, this vulnerability presents a severe risk to organizations as it enables remote code execution without requiring authentication, potentially allowing attackers to gain complete system control. The attack surface is extensive since .NET Framework is integrated into numerous Microsoft products and third-party applications, including web applications, desktop applications, and server-side components. The vulnerability can be exploited through various vectors including web applications, email attachments, or any interface that accepts user input and processes it through .NET Framework serialization mechanisms. Organizations running affected systems face potential data breaches, system compromise, and complete loss of operational control over affected infrastructure. The impact extends beyond individual system compromise to potentially enable lateral movement within networks and escalation of privileges.
Mitigation strategies for CVE-2020-0646 should prioritize immediate implementation of Microsoft security patches and updates, as the vendor released specific fixes addressing the input validation deficiencies in affected .NET Framework versions. Organizations should implement network segmentation to limit exposure and monitor for suspicious network traffic patterns that may indicate exploitation attempts. Additional protective measures include disabling unnecessary .NET Framework features, implementing strict input validation at application layers, and employing application whitelisting solutions to prevent execution of unauthorized code. Security teams should conduct comprehensive vulnerability assessments to identify all systems running affected .NET Framework versions and prioritize remediation efforts based on risk exposure. The ATT&CK framework categorizes this vulnerability under T1203 - Exploitation for Client Execution and T1059 - Command and Scripting Interpreter, highlighting the attack techniques that leverage such validation flaws for remote code execution. Organizations should also consider implementing intrusion detection systems with signatures specific to this vulnerability and establish incident response procedures to address potential exploitation attempts.