Termed “pharming” by Internet research group Netcraft, the new combination of attacks allows perpetrators to redirect users to seemingly genuine sites that even bear what appear to be correct domain names.
“Phishing is throwing the bait out and hoping to get a bite,” MX Logic CTO Scott Chasin told Government Computer News. “Pharming is planting the seeds and not trusting to chance.”
A recent scam that involved misdirecting Barclays Bank users and stealing their financial information utilized DNS wildcards and URL encoding. Instead of pointing to the bank’s legitimate site, located at http://barclays.co.uk, the email pointed to sites like http://barclays.co.uk|YJ3EMOHOqljQ8J5oW2ZKyTaRMQOahSWazTrFTEQK919VVQj6jDtyq10d24r2h0bijh2, which actually points to a third-party redirection service that instead sent surfers to a spoofed Barclays page located in Moscow.
Netcraft has also warned that attackers are beginning to use DNS cache poisoning to subvert Internet users. The group pointed to an attack that occurred on Saturday, when a group of hackers managed to exploit a known vulnerability in Symantec firewalls to inject false information into DNS servers and reroute some traffic to Google.com, eBay.com and Weather.com to three sites that attempted to install spyware on visitors’ computers.
Luckily, most URL encoding attacks are specific to certain types of systems and don’t work overall. The address above, which features a pipe character, would work on Windows XP, for example, but not on Linux.
DNS poisoning is harder to detect. One of the few options is to trace the geographic location of the website using its IP address, but even that may not paint a whole picture. For example, if users encountered a U.S. bank site that was located in Russia, it might set off alarms, but if a user encountered a U.S. Bank site that was located in Pittsburgh instead of Pennsylvania, it might seem significantly less suspicious.
“We’re starting to see some movement in this, but it is slow,” Chasing said. “We’re not trying to hawk any of these solutions. But we live in the email defense world, and pharming is a tremendous threat to our world.”
