CVE-2003-0714 in Exchange
Summary
by MITRE
The Internet Mail Service in Exchange Server 5.5 and Exchange 2000 allows remote attackers to cause a denial of service (memory exhaustion) by directly connecting to the SMTP service and sending a certain extended verb request, possibly triggering a buffer overflow in Exchange 2000.
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Analysis
by VulDB Data Team • 08/11/2025
The vulnerability identified as CVE-2003-0714 represents a critical security flaw in Microsoft Exchange Server versions 5.5 and 2000 that affects the Internet Mail Service component. This issue specifically targets the SMTP service implementation within these email servers, creating a pathway for remote attackers to exploit the system through direct network connections. The vulnerability stems from insufficient input validation and buffer management within the extended verb processing functionality of the mail service.
The technical flaw manifests when an attacker sends a specially crafted extended verb request directly to the SMTP service port, typically port 25. This particular attack vector exploits a buffer overflow condition that occurs during the processing of these extended commands. The buffer overflow vulnerability in Exchange 2000 is particularly concerning as it can lead to memory exhaustion conditions that cause the service to crash or become unresponsive. The flaw operates by sending malformed input data that exceeds the allocated buffer space, potentially leading to memory corruption that can be leveraged for more severe exploitation techniques.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it represents a fundamental security weakness in Microsoft's email server implementation. When successfully exploited, the vulnerability can cause complete service disruption for email communications, affecting business operations and potentially leading to significant downtime. The memory exhaustion effect can cause the Exchange server to become unresponsive to legitimate email traffic, effectively blocking email delivery and retrieval services. Organizations relying on these Exchange versions face substantial risk of service interruption and potential data communication failures that can impact productivity and business continuity.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which addresses buffer overflow conditions in stack-based buffers, and represents a classic example of improper input validation. The attack pattern follows techniques described in MITRE ATT&CK framework under the T1499 category for network denial of service attacks. The vulnerability's exploitation requires minimal network access and can be automated, making it particularly dangerous for unpatched systems. Organizations should implement immediate mitigations including network segmentation, firewall rules restricting SMTP access, and applying the relevant Microsoft security patches. The vulnerability also highlights the importance of proper input validation and buffer management practices in server-side applications, as recommended by secure coding standards and industry best practices for preventing similar issues in modern software development.