CVE-2021-28335 in Windows
Summary
by MITRE • 04/14/2021
Remote Procedure Call Runtime Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-28327, CVE-2021-28329, CVE-2021-28330, CVE-2021-28331, CVE-2021-28332, CVE-2021-28333, CVE-2021-28334, CVE-2021-28336, CVE-2021-28337, CVE-2021-28338, CVE-2021-28339, CVE-2021-28340, CVE-2021-28341, CVE-2021-28342, CVE-2021-28343, CVE-2021-28344, CVE-2021-28345, CVE-2021-28346, CVE-2021-28352, CVE-2021-28353, CVE-2021-28354, CVE-2021-28355, CVE-2021-28356, CVE-2021-28357, CVE-2021-28358, CVE-2021-28434.
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Analysis
by VulDB Data Team • 04/17/2021
The Remote Procedure Call Runtime Remote Code Execution Vulnerability identified as CVE-2021-28335 represents a critical security flaw within the Windows operating system's remote procedure call infrastructure. This vulnerability specifically affects the RPC runtime component that facilitates communication between different processes and systems across network boundaries. The flaw exists in how the RPC runtime handles certain input validation processes during remote procedure calls, creating an opportunity for malicious actors to execute arbitrary code on affected systems. The vulnerability is particularly concerning because it operates at a fundamental level of system communication, potentially allowing attackers to gain unauthorized access to critical system resources without requiring authentication.
The technical implementation of this vulnerability stems from improper handling of memory operations within the RPC runtime environment. Attackers can exploit this weakness by crafting specially crafted RPC requests that trigger buffer overflows or memory corruption conditions within the target system's RPC processing components. This particular vulnerability falls under the Common Weakness Enumeration category CWE-121, which describes "Stack-based Buffer Overflow" conditions, though the actual exploitation may involve more complex memory corruption techniques. The flaw allows for privilege escalation scenarios where unauthenticated remote attackers can execute malicious code with the privileges of the affected service account, potentially leading to complete system compromise. The vulnerability affects multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it a widespread concern for enterprise environments.
The operational impact of CVE-2021-28335 extends beyond simple remote code execution capabilities to encompass significant threats to organizational security posture. Organizations running affected systems face potential data breaches, system hijacking, and lateral movement opportunities for attackers who successfully exploit this vulnerability. The remote nature of the exploit means that attackers can target systems from anywhere on the network without requiring physical access or prior authentication credentials. This vulnerability can be particularly dangerous in environments where Windows RPC services are exposed to external networks or where internal network segmentation is insufficient. Security analysts have noted that the vulnerability can be leveraged as an initial access vector for more sophisticated attack chains, potentially enabling attackers to establish persistent backdoors, deploy additional malware, or conduct reconnaissance activities. The vulnerability's classification under the MITRE ATT&CK framework includes techniques such as T1071.004 for Application Layer Protocol and T1059.001 for Command and Scripting Interpreter, demonstrating the multi-faceted attack surface it creates.
Mitigation strategies for CVE-2021-28335 should prioritize immediate patch deployment through Microsoft's security updates, as the primary fix involves applying the relevant Windows updates that address the RPC runtime memory handling issues. Organizations should also implement network segmentation to limit exposure of RPC services to trusted networks only, particularly disabling unnecessary RPC ports and services. Additional defensive measures include monitoring for unusual RPC traffic patterns, implementing intrusion detection systems that can identify exploitation attempts, and conducting thorough network scans to identify potentially vulnerable systems. Security teams should also consider implementing privileged access management controls to limit the potential damage from successful exploitation attempts. The vulnerability requires careful monitoring of system logs for signs of RPC-related anomalies, as well as regular security assessments to ensure that all affected systems have been properly updated and secured against this specific threat vector. Organizations should also develop incident response procedures that specifically address RPC-based exploitation scenarios to ensure rapid containment and remediation when vulnerabilities are detected.