Abstract
DNS cache poisoning attacks have been one of the major problems on the network security. It is a serious threat that exists for a long time. Attackers forge the authorization answer and try to insert malicious IP addresses into the cache of a DNS resolver. This attack not only implies a general network attack but also can combine with the other attacks to steal the personal information. The privacy of clients who resolve DNS queries from the victim DNS resolver would be known by an attacker under the situation. In 2008, Kaminsky further enhanced this attack and reduced the time it takes from days to seconds. This issue made the network security be attached great importance again. There are so many protections have been proposed for DNS cache poisoning in several years, but it still cannot be solved perfectly. Most of them have some implementation issues to be conquer, such as key management, large-scale modification, and so on. With the wireless network becomes popular recently, wireless network devices provide more and more functions to handle these increased requires. But its security mechanism is not upgraded as the changes. One of the major service AP provides is DNSmasq, which helps to resolve DNS queries from clients like a DNS resolver. In this thesis, we try to perform the DNS cache poisoning attacks on a wireless access point. We also discuss the implementation of the existing protections on AP to resist this attack, but all of them still have some technical difficulties. Therefore, we further propose a feasible countermeasure, $ReDNS$, for this attack which is deployed on the client side and without making any change to the existing DNS systems. ReDNS uses the second reverse DNS query (PTR record) of the return IP address to verify the correctness of IP. This mechanism can not only protect the client from the theft of privacy but also solve the problems caused by multiple IP comparison. In the end of this thesis, we implement ReDNS and analyze it. The experiments show that ReDNS is a light-weight process to protect the privacy of user. And we believe that ReDNS will be a good solution which resists DNS cache poisoning attacks not only on a wired network but also on a wireless network.