CVE-2023-21702 in Windows
Summary
by MITRE • 02/14/2023
Windows iSCSI Service Denial of Service Vulnerability
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Analysis
by VulDB Data Team • 03/15/2023
The Windows iSCSI Service Denial of Service Vulnerability identified as CVE-2023-21702 represents a critical security flaw within Microsoft's storage infrastructure that affects the iSCSI service component. This vulnerability specifically targets the iSCSI Initiator service running on Windows operating systems, which is responsible for establishing and maintaining connections to iSCSI storage targets. The iSCSI protocol enables organizations to connect to storage devices over IP networks, making it a fundamental component in enterprise storage architectures and virtualization environments where data availability is paramount.
The technical flaw manifests in the improper handling of malformed or specially crafted iSCSI protocol messages during the service initialization phase. When an attacker sends malicious iSCSI packets to a vulnerable Windows system, the iSCSI service fails to properly validate incoming data structures, leading to an unhandled exception that causes the service to crash and restart. This behavior occurs because the service lacks adequate input sanitization mechanisms and robust error handling routines when processing iSCSI negotiation and authentication sequences. The vulnerability is categorized under CWE-248, which describes "Uncaught Exception" conditions where an application fails to handle exceptions properly, leading to service disruption and potential system instability.
The operational impact of this vulnerability extends beyond simple service disruption, as it can severely compromise enterprise storage availability and business continuity. Organizations relying on iSCSI-based storage solutions may experience unexpected downtime when attackers exploit this weakness, particularly in environments where automated failover mechanisms depend on consistent iSCSI service availability. The vulnerability affects multiple Windows versions including Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, and Windows Server 2022, creating widespread exposure across enterprise networks. From an attacker perspective, this vulnerability aligns with ATT&CK technique T1499.004, which focuses on "Endpoint Denial of Service" by leveraging service interruption methods to disrupt normal operations.
Mitigation strategies for CVE-2023-21702 require immediate implementation of both network-level and system-level controls to prevent exploitation. Organizations should deploy network segmentation measures to restrict iSCSI traffic to trusted networks only, implementing firewall rules that limit access to iSCSI ports 3260 and 3261 to authorized endpoints. Microsoft recommends applying the security update KB5023706 as a primary remediation measure, which includes patches to the iSCSI service that enhance input validation and exception handling. Additionally, system administrators should implement monitoring solutions to detect unusual iSCSI service restart patterns and establish automated alerting mechanisms for service disruptions. The vulnerability also highlights the importance of implementing proper network access controls and privilege separation, as outlined in the NIST Cybersecurity Framework, to minimize the attack surface and reduce the likelihood of successful exploitation.