CVE-2005-1649 in Windows
Summary
by MITRE
The IpV6 support in Windows XP SP2, 2003 Server SP1, and Longhorn, with Windows Firewall turned off, allows remote attackers to cause a denial of service (CPU consumption) via a TCP packet with the SYN flag set and the same destination and source address and port, a variant of CVE-2005-0688 and a reoccurrence of the "Land" vulnerability (CVE-1999-0016).
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Analysis
by VulDB Data Team • 09/17/2018
The vulnerability described in CVE-2005-1649 represents a critical denial of service weakness affecting IPv6 implementations in Microsoft Windows operating systems including Windows XP Service Pack 2, Windows Server 2003 Service Pack 1, and early Windows Longhorn releases. This flaw operates as a variant of previously identified vulnerabilities, specifically building upon the foundational "Land" attack pattern first documented in CVE-1999-0016 and related to CVE-2005-0688. The vulnerability exploits a fundamental flaw in how these operating systems process incoming TCP packets when IPv6 support is enabled but the Windows Firewall is disabled.
The technical mechanism behind this vulnerability involves the careful crafting of TCP packets that contain identical source and destination addresses and port numbers within the same network layer. When the vulnerable Windows systems receive such packets, they enter into a processing loop where the system attempts to handle the malformed packet in a way that consumes excessive CPU resources. This occurs because the TCP stack implementation fails to properly validate incoming packets with identical source and destination parameters, leading to an infinite loop or excessive processing cycles that effectively starve the system of computational resources.
The operational impact of this vulnerability is severe as it allows remote attackers to perform denial of service attacks against targeted systems without requiring any authentication or special privileges. The attack can be executed from anywhere on the network, making it particularly dangerous for systems with IPv6 enabled and firewall protection disabled. The sustained CPU consumption can render systems unresponsive or significantly degraded, potentially affecting network availability and service delivery. This vulnerability particularly impacts enterprise environments where IPv6 support might be enabled for future-proofing but proper security configurations are not implemented.
From a cybersecurity framework perspective, this vulnerability maps directly to CWE-129, which describes improper input validation, and relates to ATT&CK technique T1499.001 for network denial of service attacks. The vulnerability demonstrates how legacy security concepts from earlier decades can reappear in modern systems due to incomplete security testing or inadequate validation of network protocol implementations. The recurrence of the "Land" vulnerability pattern indicates that fundamental network stack validation mechanisms were not properly implemented or tested in these Windows versions, creating a persistent security gap.
Mitigation strategies for this vulnerability involve multiple layers of protection including immediate system patching for affected Windows versions, proper configuration of Windows Firewall to ensure it remains enabled, and network segmentation to limit exposure. Organizations should disable IPv6 support on systems where it is not required, implement network monitoring to detect unusual CPU consumption patterns, and establish proper access controls to prevent unauthorized remote packet injection. The vulnerability also highlights the importance of thorough security testing for protocol implementations and the necessity of maintaining up-to-date security patches across all network infrastructure components.