CVE-2002-1873 in Exchange
Summary
by MITRE
Microsoft Exchange 2000, when used with Microsoft Remote Procedure Call (MSRPC), allows remote attackers to cause a denial of service (crash or memory consumption) via malformed MSRPC calls.
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Analysis
by VulDB Data Team • 09/01/2025
The vulnerability identified as CVE-2002-1873 represents a critical denial of service weakness in Microsoft Exchange 2000 Server that specifically affects the Remote Procedure Call (MSRPC) implementation. This flaw exists within the core messaging infrastructure that facilitates distributed computing operations between networked systems, making it particularly dangerous in enterprise environments where email services remain mission-critical for business operations. The vulnerability manifests when the Exchange server processes malformed MSRPC requests that do not conform to expected protocol standards, leading to unpredictable system behavior and potential service interruption.
The technical root cause of this vulnerability lies in inadequate input validation mechanisms within the MSRPC subsystem of Exchange 2000. When the server receives malformed RPC calls, the processing logic fails to properly handle malformed data structures, causing the application to either crash or consume excessive memory resources. This behavior aligns with CWE-129, which describes improper validation of array indices, and CWE-131, which covers incorrect calculation of buffer sizes. The flaw demonstrates characteristics of a buffer overflow condition where malformed input causes the system to allocate insufficient memory or process corrupted data structures, ultimately leading to system instability.
The operational impact of this vulnerability extends beyond simple service disruption, creating significant business continuity concerns for organizations relying on Exchange 2000. Attackers can exploit this weakness to repeatedly send malformed MSRPC calls, causing sustained memory exhaustion that may require system rebooting or manual intervention to restore normal operations. This type of attack pattern corresponds to the ATT&CK technique T1499.004, which involves network denial of service attacks targeting system resources. The vulnerability is particularly concerning because it operates at the protocol level, making it difficult to distinguish from legitimate network traffic and allowing attackers to potentially consume system resources without detection.
Organizations affected by this vulnerability should implement immediate mitigations including network segmentation to limit access to Exchange services, deployment of intrusion detection systems to monitor for suspicious RPC traffic patterns, and application of Microsoft security patches released in response to this vulnerability. The recommended approach involves configuring firewalls to restrict MSRPC access to trusted network segments and implementing rate limiting mechanisms to prevent abuse of the vulnerable RPC endpoints. Additionally, system administrators should consider implementing memory monitoring solutions to detect abnormal resource consumption patterns that may indicate exploitation attempts. This vulnerability highlights the importance of proper input validation and robust error handling in distributed computing environments, as outlined in the OWASP Top Ten security principles and Microsoft's own security development lifecycle practices.