CVE-2008-1440 in Windows
Summary
by MITRE
Microsoft Windows XP SP2 and SP3, and Server 2003 SP1 and SP2, does not properly validate the option length field in Pragmatic General Multicast (PGM) packets, which allows remote attackers to cause a denial of service (infinite loop and system hang) via a crafted PGM packet, aka the "PGM Invalid Length Vulnerability."
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Analysis
by VulDB Data Team • 09/18/2018
The CVE-2008-1440 vulnerability represents a critical flaw in Microsoft Windows operating systems that affects Windows XP Service Pack 2 and 3, as well as Windows Server 2003 Service Pack 1 and 2. This vulnerability resides in the Pragmatic General Multicast protocol implementation within the Windows kernel, specifically in how the system processes option length fields within PGM packets. The flaw demonstrates a classic buffer validation issue where the operating system fails to properly validate the option length field in incoming PGM packets, creating a condition that can be exploited to trigger system instability.
The technical nature of this vulnerability stems from insufficient input validation within the network stack's PGM packet processing routine. When a malformed PGM packet containing an invalid option length field is received by an affected Windows system, the kernel's packet parsing mechanism enters an infinite loop during the validation process. This occurs because the system attempts to process the malformed option length field without proper bounds checking, causing the execution to become trapped in a continuous loop that consumes system resources and eventually results in a complete system hang. The vulnerability is categorized under CWE-129 as an insufficient validation of length fields, which is a well-documented weakness in input validation mechanisms.
From an operational perspective, this vulnerability presents a significant denial of service risk that can be exploited remotely by attackers without requiring authentication or elevated privileges. The impact extends beyond simple service disruption to potentially rendering entire systems unusable, as the infinite loop causes the system to become unresponsive to legitimate network traffic and user interactions. The vulnerability affects systems that have the PGM protocol enabled or that are configured to process PGM packets, making it particularly dangerous in enterprise environments where network services might be exposed to untrusted networks. The attack vector is straightforward, requiring only the transmission of a specially crafted PGM packet to the target system, making it a preferred choice for attackers seeking to disrupt network services.
The operational implications of this vulnerability align with ATT&CK technique T1499.004, which covers network denial of service attacks through protocol manipulation. Organizations running affected Windows systems face the risk of sustained service disruption that can impact business continuity and productivity. The vulnerability's exploitation does not require sophisticated tools or extensive knowledge, making it accessible to a broad range of threat actors. Mitigation strategies should focus on implementing network segmentation to prevent untrusted traffic from reaching vulnerable systems, disabling unnecessary network protocols, and applying the relevant Microsoft security updates that address the PGM packet validation issue. Network administrators should also consider deploying intrusion detection systems that can identify and block malformed PGM packets attempting to exploit this vulnerability. The vulnerability's persistence across multiple service packs demonstrates the importance of continuous security monitoring and timely patch management to prevent exploitation of known flaws in operating system implementations.