New system to spot malicious websites before they cause harm

Washington

Scientists are developing a new system that will make it more difficult to register websites for immoral purposes, even before the malicious users have done anything harmful.

The system called PREDATOR, developed by researchers at Princeton University in the US distinguishes between legitimate and malicious purchasers of new websites.

It yields important insights into how those two groups behave differently online even before the anything obviously bad or harmful is done.

These early signs of likely evil-doers help security professionals take preemptive measures, instead of waiting for a security threat to surface.

"The intuition has always been that the way that malicious actors use online resources somehow differs fundamentally from the way legitimate actors use them," said Nick Feamster, professor at Princeton University.

"We were looking for those signals: what is it about a domain name that makes it automatically identifiable as a bad domain name?" said Feamster.

Once a website begins to be used for malicious purposes — when it is linked to in spam email campaigns, for instance, or when it installs malicious code on visitors' machines — the defenders can flag it as bad and start blocking it.

However, by then, the site has already been used for the very kinds of behaviour that we want to prevent.

PREDATOR, which stands for Proactive Recognition and Elimination of Domain Abuse at Time-Of-Registration, gets ahead of the curve.

The researcher's techniques rely on the assumption that malicious users will exhibit registration behaviour that differs from those of normal users, such as buying and registering lots of domains at once to take advantage of bulk discounts, so that they can quickly and cheaply adapt when their sites are noticed and blacklisted.

Criminals will often register multiple sites using slight variations on names: changing words like "home" and "homes" or switching word orders in phrases.

By identifying such patterns, researchers were able to start sifting through the more than 80,000 new domains registered every day to preemptively identify which ones were most likely to be used for harm.

Testing their results against known blacklisted websites, they found that PREDATOR detected 70 per cent of malicious websites based solely on information known at the time those domains were first registered.

The false positive rate of the PREDATOR system, or rate of legitimate sites that were incorrectly identified as malicious by the tool, was only 0.35 per cent.

Being able to detect malicious sites at the moment of registration, before they are being used, can have multiple security benefits, Feamster said.

Those sites can be blocked sooner, making it difficult to use them to cause as much harm — or, indeed, any harm at all if the operators are not permitted to purchase them.  — PTI