Combosquatting is a popular technique used by hackers, spammers, and scammers to fool users into downloading malware or revealing their credentials.
Combosquatting should not be confused with typosquatting. The latter involves the purchasing of domains with transposed letters or common spelling mistakes to catch out careless typists – Fcaebook.com for example.
Combosquatting is so named because it involves the purchasing of a domain that combines a trademarked name with another word – yahoofiles.com, disneyworldamusement.info, facebook-security.com or google-privacy.com for example.
The technique is not new, but the extent that it is being used by hackers was not well understood. Now researchers at Georgia Tech, Stony Brook University and London’s South Bank University have conducted a study that has revealed the extent to which hackers, spammers, and scammers are using this technique.
The research, which was supported by the U.S. Department of Defense, National Science Foundation and the U.S. Department of Commerce, was presented at the 2017 ACM Conference on Computer and Communications Security (CCS) on October 31, 2017.
For the study, the researchers analyzed more than 468 billion DNS records, collected over 6 years, and identifed combosquatting domains. The researchers noted the number of domains being used for combosquatting has increased year over year.
The extent to which the attack method is being used is staggering. For just 268 trademarks, they identified 2.7 million combosquatting domains, which they point out makes combosquatting more than 100 times as common as typosquatting. While many of these malicious domains have been taken down, almost 60% of the domains were active for more than 1,000 days.
The team found these domains were used for a wide variety of nefarious activities, including affiliate abuse, phishing, social engineering, advanced persistent threats, malware and ransomware downloads.
End users are now being taught to carefully check domain names for typos and transposed letters to detect typosquatting, but this technique fools users into thinking they are on a website that is owned by the brand included in the domain.
First author of the study, Georgia Tech researcher Panagiotis Kintis, said, “These attacks can even fool security people who may be looking at network traffic for malicious activity. When they see a familiar trademark, they may feel a false sense of comfort with it.”
In order to prevent these types of trademark use attacks, many companies register hundreds of domains that contain their trademark. The researchers found that many of the domains being used by hackers had previously been owned by the holders of the trademark. When the domains were not renewed, they were snapped up by hackers. Many of the malicious domains that had been previously purchased by hackers, had been re-bought by other scammers when they came up for renewal.
Users are being lured onto the domains using a variety of techniques, including the placing of adverts with the combosquatting domains on ad-networks, ensuring those adverts are displayed on a wide variety of legitimate websites – a technique called malvertising. The links are also distributed in spam and phishing emails. These malicious URLS are also frequently displayed in search engine listings, and remain there until complaints are filed to have the domains removed.
Due to the prevalence of this attack technique, organizations should include it in their cyber awareness training programs to alert users to the attack method and ensure they exercise caution.
The researchers also suggest an organization should be responsible for taking these domains down and ensuring they cannot be re-bought when they are not renewed.