Infoblox Upgrades Protect Against Big Security Problems in DNS

Infoblox has updated the software powering its DNS appliance on Monday, releasing version 4.3 r2. The new rev makes your DNS infrastructure more resistant to DNS cache poisoning attacks by detecting and optionally reacting to the attack in real time. InfoBlox also added a run-time environment to the platform allowing users to create and run custom applications on the appliance. With this release, InfoBlox is setting the standard for IPAM appliances. Both features are available now.DNS cache poisoning hit public awareness with the now infamous cache poisoning problem discovered by Dan Kaminsky of IOActive. DNS server’s cache DNS address resolution “the IP addresses assigned to a hostname—responses from other DNS servers to avoid having to continually resolve a host name. Cache poisoning occurs when incorrect address resolution records are inserted into a DNS server.

Kaminsky discovered a design flaw in the DNS protocol which allows an unpatched DNS server to be tricked into storing name resolution records of the attackers choosing. For example, an attacker could redirect all users to amazon.com to a fake web site. All major DNS server software have patches available which make the attack much more difficult, but not impossible, to carry out.InfoBlox’s DNS firewall detects this attack based on behavior. The attacker has to guess two things to poison a DNS server. The first is the DNS transaction-ID that is used to match DNS responses to DNS requests. The second component is to guess which UDP source port the DNS server used to make the request. If the attacker can guess these two things correctly and get their response to the DNS server first, then the attack is successful.

The DNS cache poisoning attack is launched by getting the DNS server to request a name lookup and then firing lots of responses. In an unpatched DNS server, the cache can be poisoned in under a minute with a few thousand responses. A patched DNS server can still be poisoned in less than a day with millions of responses, but the bandwidth required makes such an attack over the Internet unlikely to succeed. The cache poisoning attack exhibits a high rate of unknown transaction-ID’s and unknown UDP source port numbers, in the hundreds per second ,or more, indicate an attack is underway. InfoBlox’s DNS firewall detects this behavior as malicious and can send an alert or simply rate limit requests from the offending host or network.

More information on this from Mike Fratto at Information Week. They have a detailed post on this topic.