CVE-2023-24940 in Windows
Summary
by MITRE • 05/09/2023
Windows Pragmatic General Multicast (PGM) Denial of Service Vulnerability
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Analysis
by VulDB Data Team • 06/01/2023
The Windows Pragmatic General Multicast (PGM) protocol vulnerability represents a critical denial of service weakness that affects Microsoft Windows operating systems. This vulnerability specifically targets the PGM transport protocol implementation within the Windows networking stack, which is designed to support multicast communication scenarios. The flaw resides in how the system processes incoming PGM packets, particularly when handling malformed or specially crafted multicast traffic that exploits memory handling inconsistencies in the kernel-level network components. According to the Common Weakness Enumeration framework, this vulnerability maps to CWE-129, which describes improper validation of array indices, indicating that the system fails to properly validate input parameters when processing multicast packet structures. The attack vector leverages the inherent complexity of multicast protocols where multiple receivers can simultaneously communicate with a single sender, creating potential points of exploitation when the protocol implementation does not adequately sanitize incoming data streams.
The technical exploitation of this vulnerability occurs when an attacker sends specifically crafted PGM packets to a target system, causing the Windows kernel to process malformed multicast data structures that trigger memory corruption or resource exhaustion conditions. The PGM protocol implementation in Windows uses a sophisticated multicast delivery mechanism that includes sequence number tracking, acknowledgment systems, and flow control mechanisms, all of which can be manipulated to cause system instability. When the kernel processes these malformed packets, it can lead to heap corruption, stack overflow conditions, or resource allocation failures that ultimately result in system crashes or complete service unavailability. The vulnerability is particularly concerning because PGM is often used in enterprise environments for high-performance multicast applications, making the impact of such an attack potentially severe for mission-critical systems. The Windows networking stack's handling of multicast traffic through PGM creates a complex attack surface where insufficient input validation allows attackers to cause the kernel to execute unintended code paths or consume excessive system resources.
From an operational perspective, this vulnerability poses significant risks to enterprise networks and organizations relying on multicast communication for applications such as video streaming, financial data distribution, or real-time collaboration systems. The denial of service impact can result in complete network service disruption, requiring system restarts and potentially causing extended downtime for critical business operations. The attack can be executed remotely without requiring authentication, making it particularly dangerous as it can be exploited by any entity with network access to the target system. Organizations using Windows systems in broadcast environments are especially vulnerable, as the PGM protocol is commonly enabled by default in many enterprise networking configurations. The vulnerability's impact extends beyond simple service interruption, as it can potentially be leveraged as a stepping stone for more sophisticated attacks, particularly when combined with other network-based exploits. According to the MITRE ATT&CK framework, this vulnerability could be categorized under T1499.004 for Network Denial of Service and potentially T1071.004 for Application Layer Protocol usage, as it involves manipulating network protocol implementations to cause service disruption.
Mitigation strategies for CVE-2023-24940 should focus on immediate patch deployment from Microsoft, as the vendor has released security updates addressing the specific memory handling issues within the PGM protocol implementation. Organizations should also implement network segmentation and access controls to limit exposure of systems running PGM services, particularly in environments where multicast traffic is not strictly required. Network monitoring solutions should be configured to detect unusual multicast traffic patterns or malformed packet structures that could indicate exploitation attempts. System administrators should disable PGM protocol support on systems where it is not essential for business operations, as this eliminates the attack surface entirely. Additionally, implementing intrusion detection systems with signature-based detection for known PGM vulnerability patterns can provide early warning capabilities. The vulnerability highlights the importance of maintaining up-to-date security patches and conducting regular vulnerability assessments of network protocol implementations. Organizations should also consider implementing network access control lists that restrict multicast traffic to only trusted sources and destinations, reducing the potential impact of such attacks. Regular security awareness training for network administrators can help identify suspicious network behavior patterns that might indicate exploitation attempts against multicast protocol implementations.