CVE-2002-0368 in Exchange
Summary
by MITRE
The Store Service in Microsoft Exchange 2000 allows remote attackers to cause a denial of service (CPU consumption) via a mail message with a malformed RFC message attribute, aka "Malformed Mail Attribute can Cause Exchange 2000 to Exhaust CPU Resources."
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Analysis
by VulDB Data Team • 05/09/2019
The vulnerability identified as CVE-2002-0368 represents a critical denial of service flaw within Microsoft Exchange 2000 Server's Store Service component. This weakness specifically targets the mail processing capabilities of the email server, enabling remote attackers to exploit a malformed RFC message attribute that triggers excessive CPU consumption. The vulnerability operates at the application layer of the OSI model, specifically affecting the messaging infrastructure that handles email processing and storage operations. The flaw demonstrates characteristics consistent with CWE-121, which describes buffer overflow conditions that can lead to resource exhaustion and system instability. The attack vector is remote and does not require authentication, making it particularly dangerous as it can be exploited by anyone with network access to the affected Exchange server.
The technical implementation of this vulnerability occurs when the Store Service processes incoming mail messages that contain malformed RFC attributes. These malformed attributes cause the server's processing logic to enter into inefficient or infinite loops during message parsing and validation. The malformed RFC message attribute specifically affects the way the server handles message headers and metadata, causing the CPU utilization to spike to 100% as the system attempts to process the invalid data. This behavior aligns with ATT&CK technique T1499.001, which covers network denial of service attacks targeting application resources. The vulnerability essentially creates a resource exhaustion condition where legitimate system processes are starved of CPU cycles, rendering the Exchange server unable to process legitimate mail traffic effectively.
The operational impact of this vulnerability extends beyond simple service disruption to encompass broader organizational risks. When exploited successfully, the attack causes sustained high CPU usage that can lead to complete service unavailability for legitimate users, effectively disabling email communication within the affected organization. This denial of service condition can persist until the system is manually restarted or the malicious message is removed from the queue. Organizations relying on Exchange 2000 for business-critical communications face significant operational disruption, potentially affecting productivity and customer service capabilities. The vulnerability also demonstrates the importance of proper input validation and error handling in enterprise messaging systems, as the lack of robust sanitization mechanisms allows malformed data to cause system-wide performance degradation.
Mitigation strategies for CVE-2002-0368 should focus on immediate patch deployment as the primary solution, with Microsoft releasing security updates specifically addressing the malformed RFC attribute processing issue. Network-level protections such as email filtering appliances and spam filters can help prevent malicious messages from reaching the Exchange server by identifying and blocking malformed RFC attributes before they reach the vulnerable Store Service. Implementing rate limiting and message queuing controls can help limit the impact of resource exhaustion attacks by controlling the rate at which messages are processed. Additionally, organizations should consider implementing monitoring solutions that can detect unusual CPU utilization patterns and alert administrators to potential exploitation attempts. The vulnerability highlights the necessity of maintaining up-to-date security patches and demonstrates the importance of network segmentation to limit the potential impact of such attacks. Organizations should also implement proper security monitoring and incident response procedures to quickly identify and respond to exploitation attempts, as the attack can cause significant disruption to email services and business operations.