Internet Forensics

DNS Record Manipulation

The DNS infrastructure of the Internet plays a critical role in resolving host and domain names into IP addresses. A great deal of effort has gone into ensuring that DNS works efficiently and is resilient in the face of server failures, incorrect data, or malicious attempts to disrupt the system. But even with these safeguards in place, the system is still subject to attack.

The potential benefit for someone involved in Internet fraud is huge. If you can change the DNS records for a major bank so that they point to your fake site, then you can potentially capture the account numbers and passwords of anyone who logs into the system. This approach sidesteps the need to send out email messages that try to get users to log in, but it does require a high level of technical sophistication. Two approaches have been used: DNS Poisoning and Pharming .

DNS servers around the Internet keep their tables updated by querying other more authoritative servers. The structure is a hierarchy with the network root servers at its origin. In a DNS poisoning attack, DNS servers are manipulated to fetch updated, incorrect DNS records from a server that has been set up by the attacker. This is a sophisticated type of attack to which modern DNS servers are largely immune. But successful attacks do still take place, usually by exploiting bugs in the server software. In March 2005, the SANS Internet Storm Center reported one such attack in which users were redirected to sites that contained ...