CVE-2024-38149 in Windows
Summary
by MITRE • 10/08/2024
BranchCache Denial of Service Vulnerability
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Analysis
by VulDB Data Team • 06/20/2026
BranchCache is a Windows networking feature designed to improve performance for remote office users by caching frequently accessed files locally at the branch office level. This vulnerability exists in the way BranchCache processes certain network requests and handles cache invalidation mechanisms. The flaw allows an attacker to send specially crafted malicious requests that cause the BranchCache service to enter an unstable state, ultimately leading to service disruption and denial of access to cached resources. The vulnerability stems from insufficient input validation and improper error handling within the BranchCache protocol implementation, specifically affecting how the service processes malformed cache entries and network messages. When exploited, this vulnerability can cause the BranchCache service to crash or become unresponsive, forcing remote office users to lose access to cached content and potentially forcing them to access files directly from the central server, which significantly impacts network performance and bandwidth utilization. The attack can be executed remotely without requiring authentication, making it particularly dangerous in enterprise environments where BranchCache is widely deployed. According to CWE classification, this vulnerability maps to CWE-20: Improper Input Validation, as the system fails to properly validate incoming network messages and cache entries. The ATT&CK framework categorizes this under T1499.004: Endpoint Denial of Service, as it specifically targets endpoint services to disrupt availability. The technical impact includes complete service disruption, potential system instability, and degradation of network performance across branch office networks. Organizations using BranchCache are particularly vulnerable if they have not applied the relevant security updates, as the vulnerability affects multiple Windows versions including Windows 7, Windows 8, Windows 10, and various server versions. The exploitation process typically involves sending malformed cache requests that trigger buffer overflows or memory corruption within the BranchCache service components. Network administrators should monitor for unusual traffic patterns or service disruptions that might indicate exploitation attempts. Mitigation strategies include applying Microsoft security patches promptly, implementing network segmentation to isolate BranchCache services, and configuring firewall rules to restrict access to BranchCache ports. Additionally, organizations should consider disabling BranchCache in environments where the risk of exploitation outweighs the performance benefits, particularly in highly secured or isolated network segments. The vulnerability demonstrates the importance of proper input validation in network services and highlights the need for comprehensive security testing of caching mechanisms that operate across distributed network environments. Organizations should also implement monitoring solutions that can detect anomalous BranchCache behavior and alert administrators to potential exploitation attempts. Regular security assessments of network infrastructure should include evaluation of caching services and their susceptibility to denial of service attacks. The impact extends beyond simple service disruption as it can cascade through the entire network infrastructure, affecting user productivity and increasing administrative overhead for troubleshooting and recovery operations.