Attacks/Breaches
8/30/2013
06:52 PM
Ehsan Foroughi
Ehsan Foroughi
Commentary
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Thwart DNS Hijackers: 5 Tips

Domain name system attacks hit The New York Times and Twitter hard last month. Here are five ways to make your DNS records harder to hack and easier to recover if they're compromised.

4. Avoid having low TTL where possible, specifically on master records.

DNS caching can delay a DNS hijacking. The higher the TTL (time to live), the longer a hijacked domain needs to stay hijacked before it can reach the masses. However, many services use low TTL; for instance, only one minute, for load-balancing purposes.

One way of avoiding low TTL on the master record in high-traffic services is to have the master record point to a number of static servers that serve a lean landing page and have all other services use a sub-domain with low TTL.

For example, you can have "your-service.com" with high TTL to serve a small landing/login page, and use "www.your-service.com" and "api.your-service.com" with low TTL service for the rest of the application. As long as the DNS records for "your-service.com" are set up with high TTL and point to your secure DNS servers, hijacking the registrar will take a fairly long time to hit the majority of users due to the caching nature of the DNS.

5. Use high TTL for MX records to delay the hijackers' ability to reroute your emails.

Despite the fact email is known to be inherently insecure, a large amount of confidential information gets passed around in email inside companies. DNS hijackers can essentially steal these emails and cause considerable damage to an organization. Using high TTL for mail exchanger (MX) records in a DNS adds a delay for hijacking emails. Using email encryption such as PGP (pretty good privacy) will also ensure that attackers can't steal the information in the emails.

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