An issue was discovered in Technitium 11.0.2. There is a vulnerability (called BadDNS) in DNS resolving software, which triggers a resolver to ignore valid responses, thus causing DoS (denial of service) for normal resolution. The effects of an exploit would be widespread and highly impactful, because the attacker could just forge a response targeting the source port of a vulnerable resolver without the need to guess the correct TXID.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Dnsserver | Technitium | 11.0.2 (including) | 11.0.2 (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.