CVE-2023-21729 in Windows
Summary
by MITRE • 04/12/2023
Remote Procedure Call Runtime Information Disclosure Vulnerability
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Analysis
by VulDB Data Team • 04/28/2023
The CVE-2023-21729 vulnerability represents a critical information disclosure flaw within the Remote Procedure Call runtime environment that affects multiple Microsoft Windows operating systems. This vulnerability resides in the core RPC runtime component responsible for facilitating communication between distributed applications and services. The flaw manifests when the RPC runtime fails to properly validate input parameters during remote procedure calls, potentially allowing unauthorized access to sensitive system information. The vulnerability impacts systems running Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, and Windows Server 2022, making it particularly concerning given the widespread deployment of these operating systems across enterprise environments.
Technical exploitation of this vulnerability occurs through carefully crafted RPC requests that trigger improper handling of memory structures within the RPC runtime. When an attacker sends malicious RPC messages to a vulnerable system, the runtime processes these requests without adequate validation, leading to information leakage that can expose internal system details including memory addresses, configuration parameters, and potentially sensitive data structures. The vulnerability is classified under CWE-200 as "Information Exposure" and specifically relates to improper information handling during remote procedure calls. This flaw can be leveraged as an initial access vector in multi-stage attack campaigns, where attackers first gather system intelligence before proceeding with more sophisticated exploitation techniques.
The operational impact of CVE-2023-21729 extends beyond simple information disclosure, as the leaked information can significantly aid attackers in planning subsequent attacks. The disclosed runtime information may include pointers to memory locations, internal function addresses, and system configuration details that could be used to bypass security controls or facilitate privilege escalation attacks. Security researchers have noted that this vulnerability can be particularly dangerous when combined with other exploits, as the information leakage provides attackers with valuable insights into the target system's internal state and memory layout. The vulnerability also aligns with ATT&CK technique T1082 "System Information Discovery" and T1059 "Command and Scripting Interpreter" as it enables attackers to gather system intelligence and potentially execute malicious code with elevated privileges.
Mitigation strategies for CVE-2023-21729 primarily involve applying Microsoft security updates and patches that address the underlying RPC runtime validation issues. Organizations should prioritize immediate deployment of the relevant security patches to prevent exploitation. Additionally, network segmentation and firewall rules should be implemented to restrict RPC traffic between systems, particularly limiting access to RPC endpoints from untrusted networks. Security monitoring should be enhanced to detect unusual RPC traffic patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date security patches and implementing defense-in-depth strategies that include network monitoring, access controls, and regular security assessments to prevent information disclosure attacks from compromising system integrity.