The Traffic Router component of the incubating Apache Traffic Control project is vulnerable to a Slowloris style Denial of Service attack. TCP connections made on the configured DNS port will remain in the ESTABLISHED state until the client explicitly closes the connection or Traffic Router is restarted. If connections remain in the ESTABLISHED state indefinitely and accumulate in number to match the size of the thread pool dedicated to processing DNS requests, the thread pool becomes exhausted. Once the thread pool is exhausted, Traffic Router is unable to service any DNS request, regardless of transport protocol.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Traffic_control | Apache | * | 1.8.0 (including) |
| Traffic_control | Apache | 1.8.1-rc0 (including) | 1.8.1-rc0 (including) |
| Traffic_control | Apache | 2.0.0-rc1 (including) | 2.0.0-rc1 (including) |
| Traffic_control | Apache | 2.0.0-rc2 (including) | 2.0.0-rc2 (including) |
| Traffic_control | Apache | 2.0.0-rc3 (including) | 2.0.0-rc3 (including) |
| Traffic_control | Apache | 2.0.0-rc4 (including) | 2.0.0-rc4 (including) |
| Traffic_control | Apache | 2.0.0-rc5 (including) | 2.0.0-rc5 (including) |
| Traffic_control | Apache | 2.0.0-rc6 (including) | 2.0.0-rc6 (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.