CVE-2022-21922 in Windows
Summary
by MITRE • 01/12/2022
Remote Procedure Call Runtime Remote Code Execution Vulnerability.
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Analysis
by VulDB Data Team • 01/15/2022
The CVE-2022-21922 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 Windows Remote Procedure Call (RPC) subsystem which serves as a fundamental component for inter-process communication across networked systems. The flaw allows attackers to execute arbitrary code on vulnerable systems with the same privileges as the RPC service itself, typically running with high system privileges. The vulnerability specifically impacts the handling of certain RPC messages and presents a significant threat to enterprise networks where RPC services are commonly utilized for system management and distributed application communication.
The technical implementation of this vulnerability stems from improper input validation within the RPC runtime library, particularly when processing malformed RPC requests. Attackers can exploit this weakness by sending specially crafted RPC messages to vulnerable systems, triggering a buffer overflow condition that leads to arbitrary code execution. The flaw occurs during the deserialization process of RPC data structures, where insufficient bounds checking allows malicious data to overwrite critical memory regions. This type of vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which covers out-of-bounds write vulnerabilities. The vulnerability can be leveraged through various attack vectors including direct network connections to RPC endpoints or through lateral movement techniques that utilize existing RPC connections.
The operational impact of CVE-2022-21922 extends far beyond individual system compromise, as RPC services are extensively used across enterprise environments for legitimate administrative functions. Organizations running affected Windows systems face potential complete network compromise, as successful exploitation can lead to privilege escalation and persistent access to critical infrastructure. The vulnerability's remote nature eliminates the need for physical access or local network presence, making it particularly dangerous for organizations with exposed RPC services. Attackers can utilize this vulnerability as a initial access vector to establish footholds within networks, potentially leading to lateral movement and data exfiltration operations. The attack surface is broad as RPC is used by numerous Windows services including Windows Management Instrumentation, Distributed Component Object Model, and various enterprise applications that rely on RPC for communication.
Organizations should implement immediate mitigations including applying Microsoft security patches released in the May 2022 Patch Tuesday updates, which specifically address this vulnerability. Network segmentation and firewall rules should be implemented to restrict RPC service access to trusted networks only, particularly blocking RPC endpoints from public internet exposure. The principle of least privilege should be enforced by limiting RPC service accounts to minimum required permissions and disabling unnecessary RPC services on systems where they are not required. Monitoring for suspicious RPC activity and implementing intrusion detection systems can help identify exploitation attempts. Security teams should also consider implementing endpoint detection and response solutions that can detect anomalous RPC behavior patterns. According to ATT&CK framework technique T1077, RPC abuse represents a common attack pattern that adversaries use to move laterally within networks, making this vulnerability particularly concerning for organizations with insufficient network monitoring and access controls. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing comprehensive network security controls to protect against remote code execution threats.