CVE-2021-1664 in Windows
Summary
by MITRE • 01/13/2021
Remote Procedure Call Runtime Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-1658, CVE-2021-1660, CVE-2021-1666, CVE-2021-1667, CVE-2021-1671, CVE-2021-1673, CVE-2021-1700, CVE-2021-1701.
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Analysis
by VulDB Data Team • 10/09/2024
The CVE-2021-1664 vulnerability represents a critical remote code execution flaw within the Remote Procedure Call runtime environment that affects multiple Microsoft Windows operating systems. This vulnerability resides in the core communication infrastructure that enables distributed applications to execute procedures on remote systems seamlessly. The flaw specifically impacts the RPC runtime component responsible for processing incoming remote procedure calls and managing the execution context for distributed computing operations. Security researchers identified this weakness as a significant threat vector that could allow attackers to execute arbitrary code on vulnerable systems without requiring authentication or user interaction.
The technical implementation of this vulnerability stems from improper input validation within the RPC runtime library. When the system processes malformed RPC requests, the runtime fails to properly validate the parameters and execution context, leading to memory corruption that can be exploited to gain unauthorized code execution privileges. The flaw manifests as a buffer overflow condition in the RPC processing pipeline, where insufficient bounds checking allows attackers to overwrite critical memory locations and redirect execution flow. This type of vulnerability typically maps to CWE-121, which describes stack-based buffer overflow conditions, and may also exhibit characteristics of CWE-787, representing out-of-bounds write vulnerabilities. The exploitation process often involves crafting malicious RPC requests that trigger the vulnerable code path, potentially enabling attackers to achieve system compromise through carefully constructed payload delivery mechanisms.
From an operational perspective, this vulnerability presents severe implications for enterprise environments where RPC services are actively utilized for inter-system communication. Organizations running Windows servers, domain controllers, and applications relying on RPC for distributed processing face heightened risk of unauthorized access and potential system takeover. The remote nature of the vulnerability means that attackers can exploit it from external networks without requiring physical access or local credentials, making it particularly dangerous for organizations with exposed RPC endpoints. Network traffic analysis reveals that RPC communication typically occurs over specific ports including 135 and dynamic ports in the 1024-5000 range, creating potential attack surfaces that security teams must monitor and protect. The vulnerability's impact extends beyond immediate system compromise to potentially enable lateral movement within networks, as successful exploitation can provide attackers with elevated privileges and access to additional system resources.
Mitigation strategies for CVE-2021-1664 should prioritize immediate patch deployment through Microsoft's security updates, as the vendor has released comprehensive fixes addressing the underlying RPC runtime flaw. Network segmentation and firewall rule enforcement can help reduce exposure by restricting RPC traffic to necessary communication paths only, particularly blocking unnecessary ports from external access. Implementing strict RPC endpoint protection measures, including disabling unnecessary RPC services and applying the principle of least privilege, significantly reduces attack surface. Security monitoring should focus on detecting anomalous RPC traffic patterns, unusual authentication attempts, and potential exploitation indicators within network logs and system event records. Organizations should also consider implementing intrusion detection systems with signatures specifically designed to identify RPC-related attack patterns and deploy endpoint protection solutions with behavioral monitoring capabilities to detect and prevent exploitation attempts. The mitigation approach aligns with ATT&CK framework techniques such as T1071.004 for application layer protocol usage and T1059.003 for command and scripting interpreter execution, ensuring comprehensive defensive measures that address both the technical vulnerability and potential exploitation vectors.