CVE-2002-0649 in SQL Server
Summary
by MITRE
Multiple buffer overflows in the Resolution Service for Microsoft SQL Server 2000 and Microsoft Desktop Engine 2000 (MSDE) allow remote attackers to cause a denial of service or execute arbitrary code via UDP packets to port 1434 in which (1) a 0x04 byte that causes the SQL Monitor thread to generate a long registry key name, or (2) a 0x08 byte with a long string causes heap corruption, as exploited by the Slammer/Sapphire worm.
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Analysis
by VulDB Data Team • 06/23/2025
The vulnerability identified as CVE-2002-0649 represents a critical security flaw in Microsoft SQL Server 2000 and Microsoft Desktop Engine 2000 Resolution Service components that operates on UDP port 1434. This vulnerability manifests as multiple buffer overflows that can be exploited remotely, creating significant risks for system availability and integrity. The flaw specifically targets the SQL Monitor thread functionality that handles network communications, making it particularly dangerous in networked environments where these services are exposed to external traffic.
The technical implementation of this vulnerability involves two distinct attack vectors that exploit different aspects of the buffer handling mechanisms within the Resolution Service. The first vector utilizes a 0x04 byte in UDP packets that triggers the SQL Monitor thread to generate excessively long registry key names, causing buffer overflow conditions that can lead to system crashes or arbitrary code execution. The second vector employs a 0x08 byte accompanied by a long string payload that results in heap corruption, a more severe form of memory corruption that provides attackers with greater opportunities for privilege escalation and system compromise. Both attack vectors leverage the inherent lack of proper input validation and boundary checking in the network protocol handling code.
The operational impact of CVE-2002-0649 extends beyond simple denial of service scenarios to encompass full system compromise capabilities. The Slammer/Sapphire worm, which exploited these vulnerabilities, demonstrated how such flaws could be weaponized for rapid propagation across networks, causing widespread disruption and system failures. The worm's exploitation of the 0x04 byte vector specifically caused systems to crash repeatedly, while the 0x08 byte vector provided more sophisticated attack capabilities. This vulnerability affected systems running Microsoft SQL Server 2000 and MSDE 2000, which were widely deployed in enterprise environments, making the potential impact substantial and far-reaching.
Security researchers have classified this vulnerability according to CWE standards, with the primary classification falling under CWE-121, which describes 'Stack-based Buffer Overflow'. The heap corruption aspect also relates to CWE-122, 'Heap-based Buffer Overflow', while the registry key name generation issue connects to CWE-125, 'Out-of-bounds Read'. The attack pattern aligns with ATT&CK framework techniques including T1190 'Exploit Public-Facing Application' and T1059 'Command and Scripting Interpreter', as the vulnerability enables remote code execution and system compromise. The exploitation of UDP port 1434 specifically relates to T1071.004 'Application Layer Protocol: DNS" and T1105 'Command and Scripting Interpreter" as attackers leverage legitimate network services for malicious purposes.
The mitigation strategies for CVE-2002-0649 involve multiple layers of defensive measures that address both immediate remediation and long-term security posture strengthening. Organizations should immediately disable the SQL Resolution Service if it is not required, particularly when the service is exposed to untrusted networks. Network segmentation through firewalls should block incoming UDP traffic on port 1434 to prevent unauthorized access attempts. Microsoft released security patches that address the buffer overflow conditions, and organizations must apply these updates promptly. Additionally, implementing network intrusion detection systems to monitor for suspicious UDP traffic on port 1434 can help detect exploitation attempts. System hardening practices including disabling unnecessary services, restricting registry access, and implementing proper network access controls provide additional protection layers against similar vulnerabilities. The vulnerability also highlights the importance of input validation and boundary checking in network services, as proper bounds checking would have prevented the buffer overflow conditions that enabled exploitation.