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.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Exchange_server | Microsoft | 5.5 (including) | 5.5 (including) |
| Exchange_server | Microsoft | 5.5-sp1 (including) | 5.5-sp1 (including) |
| Exchange_server | Microsoft | 5.5-sp2 (including) | 5.5-sp2 (including) |
| Exchange_server | Microsoft | 5.5-sp3 (including) | 5.5-sp3 (including) |
| Exchange_server | Microsoft | 5.5-sp4 (including) | 5.5-sp4 (including) |
| Exchange_server | Microsoft | 2000 (including) | 2000 (including) |
| Exchange_server | Microsoft | 2000-sp1 (including) | 2000-sp1 (including) |
| Exchange_server | Microsoft | 2000-sp2 (including) | 2000-sp2 (including) |
| Exchange_server | Microsoft | 2000-sp3 (including) | 2000-sp3 (including) |
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.