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How does IP hijacking work and how can it be prevented?

IP hijacking incidents are on the rise because IP addresses can be easily targeted. Expert Judith Myerson explains how these attacks work and how they can be prevented.

There appears to be a rise in network hijacking lately, specifically with IP addresses. How does IP hijacking work?...

How can it be prevented?

The rise in IP hijacking can partially be attributed to hackers who find the WHOIS database, for example, an easy target.

After making unauthorized changes to registration records, hackers hijack existing IP address ranges -- IPv4 and IPv6 -- from under the noses of the legitimate owners and the American Registry for Internet Numbers (ARIN). Legitimate IP address ranges issued prior to ARIN's inception in 1997 are easily hacked because they could not be revoked for lack of payment or for other reasons.

The data collected from IP hijacking can be used for spamming and other illegal activities. Fake companies have been set up to sell billions of hijacked IP addresses. Fraud, forgery and identity theft are involved with these hijackings.

For example, in 2012, the Spamhaus Project became aware of spam being sent by one of the legal IP address ranges ( It found that the original owner's contact information on WHOIS was updated to the hackers' information. Spamhaus was told that the real internet service provider (ISP) already closed the account due to nonpayment. The credit card was declined.

The ISP provided Spamhaus with emails from the fake owner. The emails showed this fake owner didn't know the real owner had passed away long before the hacker got to the real owner's records. The ISP recorded the IP address the fake owner used to log in to their customer portal, which belonged to a fake ISP. This fake ISP has been on the Spamhaus register of the top ten worst spammers.

To protect your networks from IP hijacking, consider the Spamhaus DROP lists. In addition, ARIN has reported WHOIS hacking incidents to law enforcement agencies in an effort to reduce threats related to hijacked IP addresses.

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This was last published in April 2017

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