A study from the Anti-Phishing Working Group shows phishers are increasing the use of top-level domains in their campaigns to breach security through social engineering. According to the APWG research, the .hk and .th domains lead the way with the most phishing attacks per 10,000 domains.
Gangs of phishers are stepping up their abuse of specific top-level
domains, according to a survey by the Anti-Phishing Working Group.
The study, "Global
Phishing Survey: Domain Name Use and Trends in 1H2008,"
covers the first half of 2008, surveyed 47,324 unique phishing sites located on
26,678 unique domain names. The researchers found the number of TLDs
(top-level domains) used by phishers for their attacks grew 7 percent, from 145
in the second half of 2007 to 155 in the first half of 2008.
As part of judging the pervasiveness of phishing among TLDs, the
authors measured the number of phishing attacks per 10,000 domains. The
top two TLDs in this category were .hk (Hong Kong),
which led with 142.1 phishing attacks per 10,000 domains, and .th (Thailand),
which came in second with 43.1.
The authors found that .su (Soviet Union), .ru (Russia)
and .fr (France),
ranked third, fifth and tenth respectively, received high scores in this
category because phishers launched large numbers of attacks in these TLDs via
subdomain hosting services.
"The widespread use of subdomain registration services by phishers is a
challenging development for the industry," Rod Rasmussen, co-chair of the
APWG's Internet Policy Committee, said in a statement. "These services
have diverse business models and controls, and run outside the scope of ICANN
[Internet Corporation for Assigned Names and Numbers], domain registries or any
recognized authority. This can make them an unwitting haven for phishers and in
turn adversely affect the reputation of a TLD
or registrar who has no control over their behavior."
The study also measured the number of phishing domains per 10,000 registered
domains in that TLD. In the case
of .com, there was an average of 1.6 phishing domains per
10,000, putting it at No. 71 among TLDs in that category. The .hk
domain was again first with 32.2 per 10,000.
According to the study, 4,512 subdomain sites or accounts
were used for phishing under 274 unique second-level domains. These were
established on subdomain registration services where customers set up a
subdomain under a secondary-level domain owned by the service provider.
The proportion of IP number-based phishing sites decreased 35 percent
in the same period, dropping from 18 percent in the second half of 2007 to 13
percent in the first half of 2008.
"We're seeing a trend away from fixed IP-based URLs which are readily
shut down to use of more domain-based URLs," Rasmussen explained.
"Many of these are on compromised servers which already have established
'good' reputations, while others are on fraudulently registered domain names
supported by botnets or other throw-away hosting resources."
He added, "In either case, the mitigation effort
is challenged, as one does not want to suspend an innocent domain name, while
with a botnet, the domain is the only practical choke-point to neutralize the