CVE-2024-21377 in Windows
Summary
by MITRE • 02/13/2024
Windows DNS Information Disclosure Vulnerability
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Analysis
by VulDB Data Team • 07/19/2024
This vulnerability represents a critical information disclosure flaw in the Windows Domain Name System implementation that allows unauthorized access to sensitive DNS server data. The vulnerability stems from improper access control mechanisms within the DNS server component that fails to adequately validate requests for zone transfer operations and DNS record enumeration. Attackers can exploit this weakness to obtain detailed information about DNS zones, including hostnames, IP addresses, and service records that would normally be restricted to authorized personnel only. This type of vulnerability directly maps to CWE-200 which describes insufficient output filtering and CWE-352 which covers cross-site request forgery conditions that can lead to unauthorized data access.
The technical exploitation occurs when malicious actors send specially crafted DNS queries or initiate zone transfer requests against vulnerable Windows DNS servers without proper authentication. The flaw exists in the server's response handling mechanism where it continues to provide detailed DNS record information even when access controls should prevent such disclosure. This typically manifests through TCP port 53 traffic analysis where attackers can observe responses containing complete zone data including A records, MX records, SRV records, and other service discovery information. The vulnerability affects various Windows Server versions including 2008, 2012, 2016, and 2019 platforms running DNS server roles.
The operational impact of this information disclosure vulnerability extends far beyond simple data exposure as it provides attackers with comprehensive mapping of target network infrastructure. Once obtained, this DNS information enables sophisticated attack vectors including service enumeration, target prioritization for further exploitation, and identification of potential attack surfaces within the network perimeter. Adversaries can use the disclosed information to plan targeted attacks against specific hosts, identify vulnerable services, and map out internal network topology. This vulnerability aligns with ATT&CK technique T1082 which covers system information discovery and T1590 which covers reconnaissance using multiple systems.
Mitigation strategies for this vulnerability primarily focus on implementing proper access controls and network segmentation around DNS server infrastructure. Organizations should configure DNS servers to restrict zone transfer operations to authorized secondary DNS servers only, implement proper firewall rules to limit access to TCP port 53, and ensure that DNS queries are properly authenticated before responding with detailed information. Microsoft recommends applying the latest security updates and patches that address this specific vulnerability, implementing network access control lists, and configuring DNS server properties to disable unnecessary zone transfer operations. Additionally, monitoring and logging of DNS queries should be implemented to detect anomalous access patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of principle of least privilege in network infrastructure design and highlights the critical need for proper authorization controls in DNS server implementations.