CVE-2024-21355 in Windows
Summary
by MITRE • 02/13/2024
Microsoft Message Queuing (MSMQ) Elevation of Privilege Vulnerability
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Analysis
by VulDB Data Team • 07/02/2026
Microsoft Message Queuing presents a critical elevation of privilege vulnerability that stems from improper access control mechanisms within the messaging infrastructure. This flaw allows authenticated attackers with limited system privileges to escalate their access rights and gain administrative-level control over affected systems. The vulnerability manifests in how MSMQ handles security descriptors and access control lists, creating opportunities for malicious actors to manipulate queue permissions and execute unauthorized operations. When exploited, this weakness enables adversaries to bypass normal authentication barriers and assume elevated privileges within the Windows environment.
The technical root cause of this vulnerability lies in the insufficient validation of access control entries within MSMQ's security model. Attackers can exploit this by crafting specially formatted queue messages or manipulating existing queue configurations to grant themselves additional permissions. The flaw specifically affects how the system processes privilege checks during message queuing operations, allowing unauthorized entities to escalate their privileges through legitimate system interfaces. This issue particularly impacts systems where MSMQ is actively deployed and configured with default security settings that fail to properly restrict access to sensitive messaging resources.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential data compromise and system infiltration. Once an attacker achieves elevated privileges through this vector, they can access sensitive information stored in message queues, manipulate queue configurations, and potentially establish persistent access points within the network infrastructure. The vulnerability affects various Windows operating systems including server editions and desktop variants where MSMQ components are installed and configured. Organizations with distributed messaging architectures are particularly vulnerable since the attack surface expands to include multiple interconnected systems that may share common queue resources.
Mitigation strategies for this vulnerability require immediate implementation of security patches provided by Microsoft through their regular update cycles. System administrators must ensure all affected systems receive timely updates and apply the necessary security fixes to address the access control flaws within MSMQ components. Additional protective measures include implementing strict network segmentation policies to limit access to MSMQ services, configuring proper queue permissions with least privilege principles, and monitoring queue activities for suspicious access patterns. Security teams should also consider disabling unnecessary MSMQ functionality on systems where it is not required for business operations, thereby reducing the potential attack surface.
This vulnerability aligns with several CWE classifications including CWE-276 for improper permissions and CWE-284 for improper access control. From an adversary perspective, this flaw maps to multiple ATT&CK techniques such as privilege escalation through access token manipulation and persistence mechanisms through system service manipulation. The vulnerability represents a significant concern for organizations following security frameworks like NIST SP 800-53 which emphasizes the importance of proper access control and privilege management in information systems. Organizations should conduct thorough risk assessments to identify all instances of MSMQ deployment and ensure comprehensive remediation efforts are implemented across their entire infrastructure.
The long-term implications of this vulnerability underscore the critical importance of maintaining updated security configurations and implementing robust monitoring procedures for messaging services. Regular security audits should include verification of queue permissions, access control list validation, and assessment of privilege escalation risks within enterprise messaging architectures. System administrators must also consider implementing additional security controls such as mandatory access controls and enhanced logging capabilities to detect potential exploitation attempts. The vulnerability demonstrates how legacy messaging systems can present significant security challenges when not properly maintained and updated with current security best practices.