CVE-2005-0688 in Windows
Summary
by MITRE
Windows Server 2003 and XP SP2, 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, aka a reoccurrence of the "Land" vulnerability (CVE-1999-0016).
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Analysis
by VulDB Data Team • 05/31/2019
The vulnerability described in CVE-2005-0688 represents a significant denial of service weakness that exploits a fundamental flaw in TCP packet processing within Windows Server 2003 and Windows XP SP2 systems. This issue manifests when the Windows Firewall is disabled, creating an exploitable condition that allows remote attackers to consume excessive CPU resources through carefully crafted network traffic. The vulnerability operates by sending TCP packets with specific characteristics that trigger a processing loop in the affected operating systems, effectively causing the system to become unresponsive and rendering services unavailable to legitimate users.
The technical mechanism behind this vulnerability stems from the way the Windows TCP stack handles incoming packets with identical source and destination addresses and ports. When such malformed packets are received, the system's network processing routines enter an infinite loop or significantly prolonged processing sequence, as the TCP implementation attempts to establish connections that cannot logically be completed. This behavior directly relates to the classic "Land" attack pattern first documented in CVE-1999-0016, demonstrating how fundamental protocol implementations can contain inherent flaws that persist across software versions. The vulnerability specifically targets the TCP connection establishment process where the system's response to these malformed packets becomes computationally expensive and resource-intensive.
From an operational perspective, this vulnerability presents a critical risk to network availability and system stability in environments where Windows Firewall is disabled or bypassed. Attackers can exploit this weakness by simply sending a single malformed packet to the target system, causing immediate and sustained CPU consumption that can effectively bring the system to its knees. The impact extends beyond individual system compromise to potentially affect entire network segments if multiple vulnerable systems exist within the same network. Organizations running these legacy systems without proper firewall protection face significant exposure to this attack vector, which can be executed with minimal technical expertise and resources, making it particularly dangerous in production environments.
The mitigation strategies for this vulnerability primarily focus on implementing proper network security controls and system hardening measures. The most effective immediate solution involves enabling and properly configuring the Windows Firewall, which provides protection against this specific attack pattern by filtering malformed packets before they reach the TCP stack. Network administrators should also implement ingress filtering and egress filtering policies at network boundaries to prevent malformed packets from entering the internal network. Additionally, applying security patches and updates from Microsoft that address the underlying TCP processing flaws is essential for long-term protection. The vulnerability's classification under CWE-129 and its alignment with ATT&CK technique T1499.001 for network denial of service attacks highlights the importance of comprehensive network security monitoring and the implementation of intrusion detection systems to identify and block such malicious traffic patterns.