DNS Cache Poisoning via Unvalidated UDP Responses

Dual DHCP DNS Server 8.01 improperly accepts and caches UDP DNS responses without validating that the response originates from a legitimate configured upstream DNS server. The implementation matches responses primarily by TXID and inserts results into the cache, enabling a remote attacker to inject forged responses and poison the DNS cache, potentially redirecting victims to attacker-controlled destinations.

An issue was discovered in Dual DHCP DNS Server 7.40. Due to insufficient access restrictions in the default installation directory, an attacker can elevate privileges by replacing the DualServer.exe binary.